Grape and wine analysis: Oenologists to exploit advanced test kits.
Charnock, S. C. & McCleary, B. V. (2005). Revue des Enology, 117, 1-5.
It is without doubt that testing plays a pivotal role throughout the whole of the vinification process. To produce the best possible quality wine and to minimise process problems such as “stuck” fermentation or troublesome infections, it is now recognised that if possible testing should begin prior to harvesting of the grapes and continue through to bottling. Traditional methods of wine analysis are often expensive, time consuming, require either elaborate equipment or specialist expertise and frequently lack accuracy. However, enzymatic bio-analysis enables the accurate measurement of the vast majority of analytes of interest to the wine maker, using just one piece of apparatus, the spectrophotometer (see previous issue No. 116 for a detailed technical review). Grape juice and wine are amenable to enzymatic testing as being liquids they are homogenous, easy to manipulate, and can generally be analysed without any sample preparation.
Megazyme “advanced” wine test kits general characteristics and validation.
Charnock, S. J., McCleary, B. V., Daverede, C. & Gallant, P. (2006). Reveue des Oenologues, 120, 1-5.
Many of the enzymatic test kits are official methods of prestigious organisations such as the Association of Official Analytical Chemicals (AOAC) and the American Association of Cereal Chemists (AACC) in response to the interest from oenologists. Megazyme decided to use its long history of enzymatic bio-analysis to make a significant contribution to the wine industry, by the development of a range of advanced enzymatic test kits. This task has now been successfully completed through the strategic and comprehensive process of identifying limitations of existing enzymatic bio-analysis test kits where they occurred, and then using advanced techniques, such as molecular biology (photo 1), to rapidly overcome them. Novel test kits have also been developed for analytes of emerging interest to the oenologist, such as yeast available nitrogen (YAN; see pages 2-3 of issue 117 article), or where previously enzymes were simply either not available, or were too expensive to employ, such as for D-mannitol analysis.
Microbial and physicochemical succession in fermented sausages produced with bacteriocinogenic culture of Lactobacillus sake and semi-purified bacteriocin mesenterocin Y.
Zdolec, N., Hadžiosmanović, M., Kozačinski, L., Cvrtila, Ž., Filipović, I., Škrivanko, M. & Leskovar, K. (2008). Meat Science, 80(2), 480-487.
The inﬂuence of the bacteriocinogenic culture Lactobacillus sakei (105/g) and semi-puriﬁed bacteriocin mesenterocin Y (2560 AU/kg) on the safety and quality of traditional Croatian fermented sausages was investigated. The addition of Lb. sakei and/or mesenterocin Y reduced microbial counts (P < 0.05) in the ﬁnal products. After 28 days of ripening, coagulase-negative cocci decreased 1.5–2.0 log, yeasts 1.2–1.4 log and enterococci 1.7–2.7 log. In the case of the addition of Lb. sakei, the lactic acid bacteria count was signiﬁcantly (P < 0.05) higher at day 7 of ripening, and was accompanied by a lower pH and a higher amount of lactic acid (P < 0.05). In the ﬁnal product the amount of acetic acid was signiﬁcantly lower. More intensive proteolysis and an increase in ammonia content were found at the beginning of fermentation, and in the second phase of ripening in the control samples, respectively. The free fatty acid concentration was signiﬁcantly lower during the entire ripening process compared to the control (P < 0.05). Semi-puriﬁed mesenterocin Y did not aﬀect the sensory properties of the sausages, whilst the addition of Lb. sakei enhanced them.
Effects of yeast extract and different amino acids on the dynamics of some components in cabbage juice during fermentation with Bifidobacterium lactis BB-12.
Buruleanu, C. L., Nicolescu, C. L., Avram, D., Manea, I. & Bratu, M. G. (2012). Food Science and Biotechnology, 21(3), 691-699.
Various amino acids and the yeast extract, in amounts of 0.1%(w/v), were separately tested for their influence on the analytical parameters of lactic acid fermentation of cabbage juice with Bifidobacterium animalis subsp. lactis BB-12. Compared with the control, cysteine supplementation led to a decrease of the time to reach pH 5.0 of 6 times and an increase of lactic acid productivity of 1.22 times. After 48 h the ascorbic acid content was by 360.73% higher, the fermented cabbage juices being assigned into a distinct group applying both factor analysis (FA) and cluster analysis (CA). Tryptophan contributed to better values for lactic and acetic acid yield, while lysine and yeast extract especially for acetic acid yield. Valine and leucine were not able to improve the fermentation progress, estimated through the analyzed variables. This work would provide some helpful information for the development of various lacto-fermented vegetable juices using probiotic bacteria.
Heterofermentative process in dry fermented sausages-a case report.
Kameník, J., Dušková, M., Saláková, A. & Šedo, O. (2013). Acta Veterinaria Brno, 82(2), 181-186.
In certain circumstances the fermentation process in dry fermented sausages converts to heterofermentation pathway leading to acetic acid and carbon dioxide beside lactic acid. The study describes two cases of undesirable heterofermentation in dry sausages from two different producers. In the sausage samples (n = 7) the pH value and the content of lactic and acetic acids were measured. Microbial analysis focused on quantitative and qualitative detection of lactic acid bacteria. The acetic acid content varied from 24.28 to 67.41 µmol•g-1 dry matter, in the case of samples from the second producer the content of acetic acid (48.45 to 67.41 µmol•g-1 dry matter) was higher than the lactic acid content (20.98 to 29.02 µmol•g-1 dry matter). The lactobacilli strains from the sausages were assigned to the corresponding species by Matrix-Assisted Laser Desorption-Ionization - Time of Flight Mass Spectrometry (MALDI-TOF MS) and classified to three groups according to the sugar fermentation pattern (obligately homofermentative, facultatively heterofermentative and obligately heterofermentative) and they caused the heterofermentation process in the samples of dry fermented sausages. The description of the case of heterofermentation process in dry sausages is unique and there is little information about this topic.
Effects of harvest date, wilting and inoculation on yield and forage quality of ensiling safflower (Carthamus tinctorius L.) biomass.
Cazzato, E., Laudadio, V., Corleto, A. & Tufarelli, V. (2011). Journal of the Science of Food and Agriculture, 91(12), 2298-2302.
BACKGROUND: Safflower (Carthamus tinctorius L.), usually grown as a source of oil crop, can be used as fodder either for hay or ensiling purposes, particularly in semi-arid regions.
RESULTS: A 2-year trial was conducted in southern Italy to evaluate the production and forage quality of safflower biomass cv. Centennial, harvested at three different stages: 1, at complete appearance of primary buds (PB); 2, at complete appearance of secondary and tertiary buds (STB); and 3, at 25% of flowering stage (FS). For each stage of growth, 50% of the biomass was ensiled in 4 L glass jars without and with inoculation (Lactobacillus plantarum, LAB), and the other 50% was field wilted for 24 h before ensiling. Dry matter (DM) content and yield (DMY), pH, buffering capacity (BC) and water soluble carbohydrates (WSC) were determined on fresh forage. On safflower silages were also evaluated ammonia-N, crude protein (CP), fibre fractions, fat, lactic and acetic acids, Ca and P, and gas losses. DMY ranged from 4.5 t ha-1 (PB harvesting) to 11.6 t ha-1 (FS harvesting). DM content varied from 129 g kg-1 (PB not wilted) to 630 g kg-1 (FS wilted). The WSC in forage before ensiling with not wilting ranged from 128 (PB stage) to 105 and 100 g kg-1 DM at STB and FS stages, respectively. The wilted safflower forage showed a lower WSC compared to wilted forage. The high sugar substrate allowed lactic acid fermentation and a good conservation quality in all the harvesting stages. Silages quality was strongly influenced by the treatment performed. Wilting practice increased DM, pH and NDF contents but reduced lactic acid, acetic acid and NH3-N values. Inoculation reduced DM, pH and NDF contents, but increased lactic and acetic acids, CP and ash.
CONCLUSION: As result, wilting the forage for 1 day was very effective in the early harvesting stage because this practice significantly increased DM, reducing on the same time the intensive fermentation and proteolysis processes of silage. When harvesting is performed at the beginning of the flowering stage wilting is not necessary.
Modelling the Effect of Different Substrates and Temperature on the Growth and Lactic Acid Production by Lactobacillus amylovorus DSM 20531T in Batch Process.
Trontel, A., Baršić, V., Slavica, A., Santek, B. & Novak, S. (2010). Food Technology & Biotechnology, 48(3), 352-361.
Amylolytic lactic acid bacterium Lactobacillus amylovorus DSM 20531T utilised glucose, sucrose and starch as a sole carbon and energy source. The three substrates were completely depleted from MRS medium during batch cultivations carried out in a laboratory scale stirred tank bioreactor at constant temperature (40°C) and pH value (5.5). Under the tested conditions, the bacterium was capable of conducting simultaneously starch hydrolysis and fermentation. A mixture of two stereoisomers, D-(-)- and L-(+)-lactic acid, was produced in all cases by highly efficient homofermentative bioprocess with 0.93 to 1 g of lactate produced per g of total (consumed) substrate. The effect of temperature on the kinetics of cell growth and lactic acid production by the amylolytic strain in the starch-containing medium was also investigated. Efficient simultaneous saccharification and fermentation (SSF) was obtained at 35, 40 and 45°C with completely degraded complex carbohydrate in 8 to 12 h and the product yield coefficient in the range from 0.91 to 0.93 g/g. Maximum values for substrate consumption rate (0.89 h-1), maximum specific growth rate (0.87 h-1), product formation rate (2.01 h-1), and productivity of lactic acid (1.45 g/(Uh)) were obtained at 45°C, while maximum biomass concentration (4.38 g/L) was attained at 40°C. The ratio of the two stereoisomeric forms of produced lactic acid was strongly affected by the temperature. Unstructured kinetic model was used to describe the consumption of the three substrates, bacterial biomass formation and lactic acid production by L. amylovorus DSM 20531T. The dependence of biokinetic parameters on temperature was described by cardinal temperature model. The applied models successfully predicted all experimental data.
Lactose fermentation by Kombucha – a process to obtain new milk–based beverages.
Iličić, M., Kanurić, K., Milanović, S., Lončar, E., Djurić, M. & Malbaša, R. (2012). Romanian Biotechnological Letters, 17(1), 7013-7021.
This paper focuses on fermentation of lactose from a model system (black tea) and from two types of milk (0.9% w/w and 2.2% w/w of fat) by application of Kombucha. Quantities of the applied Kombucha starter were 10% v/v and 15% v/v. All fermentations were performed at 42°C. The process to achieve a desirable pH=4.5 was slower in the model system (16 h) than in milks (9 - 10 h). Regarding starter quantity, 10% v/v proved the optimal. Regarding types of milk, higher fat content guarantees shorter fermentation and higher yield of metabolites. Utilization of lactose was found at a level of ≈20% and ≈30% in milks with 0.9% w/w and 2.2% w/w of fat, respectively. This was correlated with an appearance of intermediates and/or products. Glucose underwent further transformations almost entirely, while galactose showed much lower reactivity. Seven to twelve times higher contents of lactic acid were found compared to acetic acid. Milk-based beverage from the reduced fat sample, inoculated with 10% v/v of Kombucha starter, has the best physical characteristics (syneresis and water holding capacity). It also developed a good texture (especially cohesiveness and index of viscosity). Milk lactose fermentation was a process that could have been used for obtaining new milk-based products.
Simultaneous saccharification and high titer lactic acid fermentation of corn stover using a newly isolated lactic acid bacterium Pediococcus acidilactici DQ2.
Zhao, K., Qiao, Q., Chu, D., Gu, H., Dao, T. H., Zhang, J. & Bao, J. (2013). Bioresource Technology, 135, 481-489.
A lactic acid bacterium with high tolerance of temperature and lignocellulose derived inhibitor was isolated and characterized as Pediococcus acidilactici DQ2. The strain used in the simultaneous saccharification and fermentation (SSF) for high titer lactic acid production at the high solids loading of corn stover. Corn stover was pretreated using the dry sulphuric acid pretreatment, followed by a biological detoxification to remove the inhibitors produced in the pretreatment. The bioreactor with a novel helical impeller was used to the SSF operation of the pretreated and biodetoxified corn stover. The results show that a typical SSF operation at 48°C, pH 5.5, and near 30% (w/w) solids loading in both 5 and 50 L bioreactors was demonstrated. The lactic acid titer, yield, and productivity reached 101.9 g/L, 77.2%, and 1.06 g/L/h, respectively. The result provided a practical process option for cellulosic lactic acid production using virgin agriculture lignocellulose residues.
Biohydrogen and methane production from cheese whey in a two-stage anaerobic process.
Antonopoulou, G., Stamatelatou, K., Venetsaneas, N., Kornaros, M. & Lyberatos, G. (2008). Industrial & Engineering Chemistry Research, 47(15), 5227-5233.
The aim of the present study was to investigate the potential of hydrogen and subsequent methane production from raw cheese whey at 35°C. The fermentative hydrogen production process from raw cheese whey was conducted in a continuous-type stirred tank bioreactor, operated at low hydraulic retention time (HRT; 24 h). In this stage, the carbohydrates contained in cheese whey are fermented to a mixture of acids and a gaseous mixture rich in hydrogen. The continuous fermentative hydrogen production was sustained by the indigenous microflora already contained in the raw cheese whey because the bioreactor was not seeded with any source of inoculum. At a HRT of 24 h, the hydrogen production rate was 7.53 L of H2/day, while the yield of hydrogen produced was 0.041 m3 of H2/kg of chemical oxygen demand (COD) added or 2.49 L of H2/L of cheese whey. The mixed liquor from this stage was further digested to biogas in a periodic anaerobic baffled reactor (PABR), a baffled-type bioreactor. The PABR was operated at HRTs of 20, 10, and 4.4 days. The highest biogas and methane production rates were 105.9 L of biogas/day and 75.6 L of CH4/day, respectively, and were obtained at an HRT of 4.4 days. During this stage, COD reduction reached 94%, obtained at an HRT of 4.4 days. Furthermore, the methane potential of the raw cheese whey was assessed by conducting a biochemical methane potential test. It was estimated to be 0.31 m3 of CH4 /kg of COD added or 17.9 L of CH4/L of cheese whey. This work demonstrated that biohydrogen production from cheese whey can be very efficiently coupled with methane production in a subsequent step, exploiting the gaseous biofuel potential of this wastewater type.
Production of functional Ricotta Cheese.
Niro, S., Succi, M., Cinquanta, L., Fratianni, A., Tremonte, P., Sorrentino, E. & Panfili, G. (2013), Dairy Ingredients, 24(6), 56-59.
In this work, the suitability of Ricotta cheese as a food carrier for functional ingredients was evaluated. The probiotic strain Lactobacillus paracasei subsp. paracasei F19, inoculated at a concentration of 109 cfu/serving size, maintained high counts during the cold storage of Ricotta cheese (7 days at 5°C), without altering the nutritional and sensorial properties of Ricotta samples. Similarly, the addition of 3% inulin did not significantly change the sensory profile of the cheese, whereas the addition of chestnut flour lowered the perceived sensory characteristics. The synbiotic formulation (with 3% inulin and 109 cfu/serving size of Lb. paracasei subsp. paracasei F19) altered the Ricotta sensorial characteristics, mainly for an excessive acidification.
Responses in digestion, rumen fermentation and microbial populations to inhibition of methane formation by a halogenated methane analogue.
Mitsumori, M., Shinkai, T., Takenaka, A., Enishi, O., Higuchi, K., Kobayashi, Y., Nonaka, I., Asanuma, N., Denman, S. E. & McSweeney, C. S. (2012). British Journal of Nutrition, 108(03), 482-491.
The effects of the anti-methanogenic compound, bromochloromethane (BCM), on rumen microbial fermentation and ecology were examined in vivo. Japanese goats were fed a diet of 50% Timothy grass and 50% concentrate and then sequentially adapted to low, mid and high doses of BCM. The goats were placed into the respiration chambers for analysis of rumen microbial function and methane and H2 production. The levels of methane production were reduced by 5, 71 and 91%, and H2 production was estimated at 545, 2941 and 3496 mmol/head per d, in response to low, mid and high doses of BCM, respectively, with no effect on maintenance feed intake and digestibility. Real-time PCR quantification of microbial groups showed a significant decrease relative to controls in abundance of methanogens and rumen fungi, whereas there were increases in Prevotella spp. and Fibrobacter succinogenes, a decrease in Ruminococcus albus and R. flavefaciens was unchanged. The numbers of protozoa were also unaffected. Denaturing gradient gel electrophoresis and quantitative PCR analysis revealed that several Prevotella spp. were the bacteria that increased most in response to BCM treatment. It is concluded that the methane-inhibited rumen adapts to high hydrogen levels by shifting fermentation to propionate via Prevotella spp., but the majority of metabolic hydrogen is expelled as H2 gas.
The effect of transglutaminase on rheology and texture of fermented milk products.
Iličić, M. D., Milanović, S. D., Carić, M. Ð., Vukić, V. R., Kanurić, K. G., Ranogajec, M. I. & Hrnjez, D. V. (2013). Journal of Texture Studies, 44(2), 160-168.
The aim of this study was to investigate the effect of transglutaminase (TG) addition on rheological properties, textural characteristics and microstructure of fermented milk products manufactured by different starters (probiotics and kombucha inoculum). Rheological analysis revealed that all manufactured fermented milk products had higher storage modulus than loss modulus and exhibited thixotropic and a typical shear thinning behavior. The addition of TG in milk increased approximately 10.5% hysteresis loop area, 39% firmness and 48% consistency in sample produced with probiotic starter and had more firm and stable gel structure than kombucha fermented milk products. The scanning electron microscopy micrographs showed that casein matrix of fermented milk products containing TG is continuous and uninterrupted except for void spaces occupied by milk serum and starter culture cell.
Bifidobacterium commune sp. nov. isolated from the bumble bee gut.
Praet, J., Meeus, I., Cnockaert, M., Aerts, M., Smagghe, G. & Vandamme, P. (2015). Antonie Van Leeuwenhoek, 107(5), 1307-1313.
Bifidobacteria were isolated from the gut of Bombus lapidarius, Bombus terrestris and Bombus hypnorum bumble bees by direct isolation on modified trypticase phytone yeast extract agar. The MALDI-TOF MS profiles of four isolates (LMG 28292T, R-53560, R-53124, LMG 28626) were found to be identical and did not cluster with the profiles of established Bifidobacterium species. Analysis of the 16S rRNA gene sequence of strain LMG 28292T revealed that LMG 28292T is most closely related to the Bifidobacterium bohemicum type strain (96.8 %), which was also isolated from bumble bee gut specimens. The hsp60 gene of strain LMG 28292T shows 85.8 % sequence similarity to that of the B. bohemicum type strain. The (GTG) 5-PCR profiles and the hsp60 sequences of all four isolates were indistinguishable; however, three different phenotypes were observed among the four isolates by means of the API 50CHL microtest system. Based on the phylogenetic, genotypic and phenotypic data, we propose to classify the four isolates within the novel species Bifidobacterium commune sp. nov., with LMG 28292T (= DSM 28792T) as the type strain.
Novel lactic acid bacteria isolated from the bumble bee gut: Convivina intestini gen. nov., sp. nov., Lactobacillus bombicola sp. nov., and Weissella bombi sp. nov.
Praet, J., Meeus, I., Cnockaert, M., Houf, K., Smagghe, G. & Vandamme, P. (2015). Antonie van Leeuwenhoek, 107(5), 1337-1349.
Twelve isolates of lactic acid bacteria (LAB) were obtained in the course of a bumble bee gut microbiota study and grouped into four matrix-assisted laser desorption/ionisation time-of-flight mass spectrometry clusters. Comparative 16S rRNA gene sequence analysis revealed that cluster 1 isolates, represented by strain LMG 28288T, are most closely related to Lactobacillus apis (97.0 % sequence similarity to that of L. apis LMG 26964T). Cluster 2 isolates represented by strain LMG 28290T are most closely related to Weissella hellenica (99.6 % sequence similarity to that of W. hellenica LMG 15125T). The single cluster 3 and 4 isolates had identical 16S rRNA gene sequences which were 94.8 % similar to that of Leuconostoc mesenteroides subsp. mesenteroides LMG 6893T, their nearest phylogenetic neighbour. A polyphasic taxonomic study additionally including comparative pheS sequence analysis, DNA-DNA hybridization experiments, DNA G+C content analysis, (GTG)5-PCR fingerprinting and a biochemical characterization, demonstrated that cluster 1 isolates represent a novel Lactobacillus species for which we propose the name Lactobacillus bombicola sp. nov. with LMG 28288T (= DSM 28793T) as the type strain; and that cluster 2 isolates represent a novel Weissella species for which we propose the name Weissella bombi sp. nov. with LMG 28290T (= DSM 28794T) as the type strain. Cluster 3 and 4 isolates, in contrast, represented a very distinct, novel taxon that could be distinguished from members of the genera Leuconostoc and Fructobacillus, its nearest phylogenetic neighbours, by its cellular morphology, non-fructophilic metabolism and DNA G+C content. We therefore classify both isolates into a novel species representing a novel LAB genus for which the name Convivina intestini gen. nov., sp. nov. is proposed with LMG 28291T (= DSM 28795T) as the type strain.
Hyper glucansucrase, glucan and oligosaccharide producing novel Weissella cibaria RBA12 isolated from Pummelo (Citrus maxima).
Baruah, R. & Goyal, A. (2015). Annals of Microbiology, 65(4), 2301-2310.
Weissella cibaria RBA12 (GenBank accession no: KF515952) producing glucansucrase and glucan was isolated from pulp of Pummelo (Citrus maxima). The isolate RBA12 was characterized and identified on the basis of morphological, biochemical properties and 16S rRNA gene sequence analysis, and gave maximum glucansucrase activity of 7.2 U/mL at 20°C and 180 rpm. The molecular mass of crude glucansucrase was approximately 180 kDa as determined by SDS-PAGE analysis and was confirmed as glucansucrase by periodic acid-Schiff staining using sucrose as substrate. Maximum glucan concentration of 8.3 mg/mL with an efficiency of glucan production of 83 % was observed in the cell-free supernatant under optimized conditions of growth of W. cibaria RBA12. The production of oligosaccharides by W. cibaria RBA12 was carried out by supplementing fermentation medium with maltose as an acceptor molecule. The time-dependent analysis of the acceptor reaction in the medium by TLC and ESI-TOF-MS revealed that W. cibaria RBA12 produced oligosaccharides ranging from tri-saccharides to homologous penta-saccharides.
Development of a multi‐parameter sensor chip for the simultaneous detection of organic compounds in biogas processes.
Pilas, J., Iken, H., Selmer, T., Keusgen, M. & Schöning, M. J. (2015). Physica Status Solidi (a) , 212(6), 1306-1312.
An enzyme-based multi-parameter biosensor is developed for monitoring the concentration of formate, D-lactate, and L-lactate in biological samples. The sensor is based on the specific dehydrogenation by an oxidized β-nicotinamide adenine dinucleotide (NAD+)-dependent dehydrogenase (formate dehydrogenase, D-lactic dehydrogenase, and L-lactic dehydrogenase, respectively) in combination with a diaphorase from Clostridium kluyveri (EC 220.127.116.11). The enzymes are immobilized on a platinum working electrode by cross-linking with glutaraldehyde (GA). The principle of the determination scheme in case of L-lactate is as follows: L-lactic dehydrogenase (l-LDH) converts L-lactate into pyruvate by reaction with NAD+. In the presence of hexacyanoferrate(III), the resulting reduced β-nicotinamide adenine dinucleotide (NADH) is then regenerated enzymatically by diaphorase. The electrochemical detection is based on the current generated by oxidation of hexacyanoferrate(II) at an applied potential of +0.3 V vs. an Ag/AgCl reference electrode. The biosensor will be electrochemically characterized in terms of linear working range and sensitivity. Additionally, the successful practical application of the sensor is demonstrated in an extract from maize silage.
L-Lactic acid fermentation by Enterococcus faecium: a new isolate from bovine rumen.
Sun, W., Liu, J., Xu, H., Li, W. & Zhang, J. (2015). Biotechnology Letters, 37(7), 1379-1383.
Objectives: To obtain a novel adaptable stain that can produce enantioselective L-lactic acid efficiently, reduce the operational cost of fermentation process and be suitable for scale production. Results: Enterococcus faecium S.156 produced 126 g L-lactic acid/l with high optical purity (99.7 %), high productivity (5.25 g/l.h) and a conversion ratio >90 %. L-lactic acid production remained steady from 32 to 40°C and at pH values from 5.5 to 6.5. O2 made no difference to both biomass growth and the L-lactic acid fermentation. 8 mg folic acid/l combined with 2 mM Fe2+ substituted for 6 g yeast extract/l, which is a cost-saving. Conclusions: The special characteristics and economic traits of E. faecium S.156 make it suitable for industrial-scale production of L-lactic acid.
Pork meat products functional value and safety parameters improving by using lactic acid fermentation of savory plants.
Bartkiene, E., Mozuriene, E., Juodeikiene, G., Zadeike, D., Maruska, A., Stankevicius, M., Ragazinskiene, O. & Cizeikiene, D. (2015). Journal of Food Science and Technology, 52(11), 7143-7152.
The nutritional strategies to improve the quality of food products of animal origin are relatively new approach. In this work the solid state fermentation (SSF) and traditional submerged fermentation (TF) with bacteriocin-like inhibitory substances (BLIS) producing lactic acid bacteria was applied for treatment of Satureja montana L. plants (SMP). The effect of fermented SMP additives on ready-to-cook minced pork (RCMP) quality and safety was studied. Viability of LAB in SMP medium significantly (p < 0.05) depended on type of fermentation (TF and SSF). Supplementation of RCMP with SSF SMP reduced the growth of mesophilic bacteria up to 34 % during 120 h storage, while TF SMP additives had lower effect (up to 17.4 %) compared to control sample. The highest antimicrobial activity against pathogens showed SSF SMP additives fermented with P. acidilactici. Sensory analysis indicated the significant (p < 0.05) acceptability increase of RCMP prepared with 3 % SSF SMP additives. The addition of SMP increased tenderness and water holding capacity and enriched the RCMP with biologically active compounds such as ρ-cimene, γ-terpinene and carvacrol. Both types of SMP fermented with tested LAB strains influenced the significant (p < 0.05) reduction of total biogenic amines in the RCMP (to 0.3 mg/kg d.w.) compared to control sample (43.96 mg/kg d.w.). SMP fermented with BLIS producing LAB could be a good alternative for RCMP processing to prevent meat decolouration and microbial spoilage, thus increasing acceptability and shelf-life of meat products.
Distillery wastes to lactic acid: Bio refinery approach.
Đukić-Vuković, A., Mojović, L., Pejin, J. & Kocić-Tanackov, S. (2015). Journal on Processing and Energy in Agriculture, 19(1), 34-37.
The costs of wastewater treatment distillatory significantly affect the total cost of production of bioethanol. In addition to the traditional use distillatory waste water or stillage in feeding livestock, complex chemical composition stillage provides alternative possibilities of utilization. Complete distillatory Stillage from the production of bioethanol waste bread is used as a substrate for lactic acid fermentation using Lactobacillus rhamnosus ATCC 7469 to produce lactic acid, probiotics and feed. The concentration of lactic acid, the number of living cells and the concentration of reducing sugars were monitored during fermentation. Lactic acid fermentation liquid stillage distillatory work was performed in batches with free and immobilized biocatalysts, and also with recikulacijom batch using immobilized biomass on zeolite. The acidic lactic fermentation whole stillage is achieved by a high concentration of lactic acid and the fermented solid residue stillage proved adequate properties for use in feeding monogastric animals. Both types of substrates, the liquid portion of stillage and complete Stillage enable efficient production of lactic acid with the productivity of about 1.80 g L-1 h-1, or produce various by-products. The first strategy allows the use of liquid stillage work for the production of lactic acid and probiotic supplementation valuable animals (with the number of living cells of more than 1010 CFU ml-1) with the possibility of utilization of residual fermented stillage work for the production of animal feed. Another strategy involves the fermentation of whole stillage which occur parallel to lactic acid fermented solids and as a highly valuable food for monogastric animals. In both processes was not necessary stillage enriched with minerals not not with expensive sources of nitrogen. PR This work was funded by the Serbian Ministry of Education, Science and Technological Development (TR 31017).
Non-traditional sources for isolation of lactic acid bacteria.
Teneva-Angelova, T. & Beshkova, D. (2016). Annals of Microbiology, 66(1), 449-459.
In recent years there has been increasing interest in lactic acid bacteria isolated from non-dairy products, due to their diverse metabolic profile, unique flavor-forming activities, and potential for use as starters or starter adjuncts for the dairy industry. Screening of 400 microbial isolates obtained from the herbs Geranium sanguineum L., Hypericum perforatum L., and Panax ginseng C.A. Meyer was performed, and 64 isolates were selected based on milk coagulation and gas formation ability and non-specific odour. Using tests involving multiple transfer and growth in selective and differential media, 258 single colonies were isolated, of which 98 were affiliated with the lactic acid bacteria group. These bacteria are homofermentative cocci and rods with a wide pH (5.0-9.6) and temperature range (15-45°C), high salt tolerance (3.0-10.0 % NaCl), and high acid-producing activity (3.50-12.00 g/L). With the use of genotype-based methods, the plant isolates were identified at the species level as Enterococcus faecium, Streptococcus thermophilus and Lactobacillus rhamnosus.
Formation of volatile compounds in kefir made of goat and sheep milk with high polyunsaturated fatty acid content.
Cais-Sokolińska, D., Wójtowski, J., Pikul, J., Danków, R., Majcher, M., Teichert, J., & Bagnicka, E. (2015). Journal of Dairy Science, 98(10), 6692-6705.
This article explored the formation of volatile compounds during the production of kefir from goat and sheep milks with high polyunsaturated fatty acids (PUFA) as a result of feeding animals forage supplemented with maize dried distillers grains with solubles (DDGS). The increased PUFA content of the goat and sheep milks resulted in significant changes to the fermentation process. In particular, apart from an increase in the time taken to ferment sheep milk, fermentation yielded less 2,3-butanedione. The highest quantities of this compound were assayed in kefir produced from goat milk with an increased content of PUFA. An increase of PUFA significantly elevated ethanal synthesis during lactose-alcohol fermentation of sheep milk. Neither the origin of milk (sheep or goat) nor the level of PUFA had any statistical effect on the amount of ethanal assayed during the fermentation of milk and within the finished product. The proportion of l(+)-lactic acid was higher in kefirs produced using goat milk compared with sheep milk and did not depend on the content of PUFA in milk fat. The content of PUFA had a significant effect on the aroma profile of the resulting kefirs. An increase in PUFA content resulted in the loss of whey aroma in goat milk kefirs and the animal odor in sheep milk kefirs, and a creamy aroma became more prevalent in kefirs made from sheep milk.
Treatment of grain with organic acids at 2 different dietary phosphorus levels modulates ruminal microbial community structure and fermentation patterns in vitro.
Harder, H., Khol-Parisini, A., Metzler-Zebeli, B. U., Klevenhusen, F. & Zebeli, Q. (2015). Journal of dairy science, 98(11), 8107-8120.
Recent data indicate positive effects of treating grain with citric (CAc) or lactic acid (LAc) on the hydrolysis of phytate phosphorus (P) and fermentation products of the grain. This study used a semicontinuous rumen simulation technique to evaluate the effects of processing of barley with 50.25 g/L (wt/vol) CAc or 76.25 g/L LAc on microbial composition, metabolic fermentation profile, and nutrient degradation at low or high dietary P supply. The low P diet [3.1 g of P per kg of dry matter (DM) of dietary P sources only] was not supplemented with inorganic P, whereas the high P diet was supplemented with 0.5 g of inorganic P per kg of DM through mineral premix and 870 mg of inorganic P/d per incubation fermenter via artificial saliva. Target microbes were determined using quantitative PCR. Data showed depression of total bacteria but not of total protozoa or short-chain fatty acid (SCFA) concentration with the low P diet. In addition, the low P diet lowered the relative abundance of Ruminococcus albus and decreased neutral detergent fiber (NDF) degradation and acetate proportion, but increased the abundance of several predominantly noncellulolytic bacterial species and anaerobic fungi. Treatment of grain with LAc increased the abundance of total bacteria in the low P diet only, and this effect was associated with a greater concentration of SCFA in the ruminal fluid. Interestingly, in the low P diet, CAc treatment of barley increased the most prevalent bacterial group, the genus Prevotella, in ruminal fluid and increased NDF degradation to the same extent as did inorganic P supplementation in the high P diet. Treatment with either CAc or LAc lowered the abundance of Megasphaera elsdenii but only in the low P diet. On the other hand, CAc treatment increased the proportion of acetate in the low P diet, whereas LAc treatment decreased this variable at both dietary P levels. The propionate proportion was significantly increased by LAc at both P levels, whereas butyrate increased only with the low P diet. Treatments with CAc or LAc reduced the degradation of CP and ammonia concentration compared with the control diet at both P levels. In conclusion, the beneficial effects of CAc and LAc treatment on specific ruminal microbes, fermentation profile, and fiber degradation in the low P diet suggest the potential for the treatment to compensate for the lack of inorganic P supplementation in vitro. Further research is warranted to determine the extent to which the treatment can alleviate the shortage of inorganic P supplementation under in vivo conditions.
Enterococcus bulliens sp. nov., a novel lactic acid bacterium isolated from camel milk.
Kadri, Z., Spitaels, F., Cnockaert, M., Praet, J., El Farricha, O., Swings, J. & Vandamme, P. (2015). Antonie van Leeuwenhoek, 108(5), 1257-1265.
Four lactic acid bacteria isolates obtained from fresh dromedary camel milk produced in Dakhla, a city in southern Morocco, were characterised in order to determine their taxonomic position. The four isolates had highly similar MALDI-TOF MS and RAPD fingerprints and identical 16S rRNA gene sequences. Comparative sequence analysis revealed that the 16S rRNA gene sequence of the four isolates was most similar to that of Enterococcus sulfureus ATCC 49903T and Enterococcus italicus DSM 15952T (99.33 and 98.59 % similarity, respectively). However, sequence analysis of the phenylalanyl-tRNA synthase (pheS), RNA polymerase (rpoA) and ATP synthase (atpA) genes revealed that the taxon represented by strain LMG 28766T was well separated from E. sulfureus LMG 13084T and E. italicus LMG 22039T, which was further confirmed by DNA-DNA hybridization values that were clearly below the species demarcation threshold. The novel taxon was easily differentiated from its nearest neighbour species through sequence analysis of protein encoding genes, MALDI-TOF mass spectrometry and multiple biochemical tests, but had a similar percentage G+C content of about 39 %. We therefore propose to formally classify these isolates as Enterococcus bulliens sp. nov., with LMG 28766T (=CCMM B1177T) as the type strain.
Faecalibacterium prausnitzii subspecies-level dysbiosis in the human gut microbiome underlying atopic dermatitis.
Song, H., Yoo, Y., Hwang, J., Na, Y. C. & Kim, H. S. (2016). Journal of Allergy and Clinical Immunology, 137(3), 852-860.
Background: Atopic dermatitis (AD) is a serious global epidemic associated with a modern lifestyle. Objective: Although aberrant interactions between gut microbes and the intestinal immune system have been implicated in this skin disease, the nature of the microbiome dysfunction underlying the disease remains unclear. Methods: The gut microbiome from 132 subjects, including 90 patients with AD, was analyzed by using 16S rRNA gene and metagenome sequence analyses. Reference genomes from the Human Microbiome Project and the KEGG Orthology database were used for metagenome analyses. Short-chain fatty acids in fecal samples were compared by using gas chromatographic–mass spectrometric analyses. Results: We show that enrichment of a subspecies of the major gut species Faecalibacterium prausnitzii is strongly associated with AD. In addition, the AD microbiome was enriched in genes encoding the use of various nutrients that could be released from damaged gut epithelium, reflecting a bloom of auxotrophic bacteria. Fecal samples from patients with AD showed decreased levels of butyrate and propionate, which have anti-inflammatory effects. This is likely a consequence of an intraspecies compositional change in F prausnitzii that reduces the number of high butyrate and propionate producers, including those related to the strain A2-165, a lack of which has been implicated in patients with Crohn disease. Conclusions: The data suggest that feedback interactions between dysbiosis in F prausnitzii and dysregulation of gut epithelial inflammation might underlie the chronic progression of AD by resulting in impairment of the gut epithelial barrier, which ultimately leads to aberrant TH2-type immune responses to allergens in the skin.
Engineering wild-type robust Pediococcus acidilactici strain for high titer L-and D-lactic acid production from corn stover feedstock.
Yi, X., Zhang, P., Sun, J., Tu, Y., Gao, Q., Zhang, J., & Bao, J. (2016). Journal of Biotechnology, 217, 112-121.
Pediococcus acidilactici TY112 producing L-lactic acid and P. acidilactici ZP26 producing D-lactic acid, were engineered from the wild-type P. acidilactici DQ2 by ldhD or ldh gene disruption, and the robustness of the wild-type strain to the inhibitors derived from lignocellulose pretreatment was maintained well. In simultaneous saccharification and fermentation (SSF), 77.66 g L-1 of L-lactic acid and 76.76 g L-1 of D-lactic acid were obtained at 25% (w/w) solids content of dry dilute acid pretreated and biodetoxified corn stover feedstock. L- and D-Lactic acid yield and productivity were highly dependent on the inhibitor removal extent due to the significant down-regulation on the expressions of ldh and ldhD encoding lactate dehydrogenase by inhibitor, especially syringaldehyde and vanillin at the low concentrations. This study provided a prototype of industrial process for high titer L- and D-lactic acid production from lignocellulose feedstock.