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Background: The market for beverages is highly changing within the last years. Increasing consumer awareness towards healthier drinks led to the revival of traditional and the creation of innovative beverages. Various protein-rich legumes were used for milk analogues, which might be also valuable raw materials for refreshing, protein-rich beverages. However, no such applications have been marketed so far, which might be due to unpleasant organoleptic impressions like the legume-typical "beany" aroma. Lactic acid fermentation has already been proven to be a remedy to overcome this hindrance in consumer acceptance., Results: In this study, a statistically based approach was used to elucidate the impact of the fermentation parameters temperature, inoculum cell concentration, and methionine addition on the fermentation of lupine- and faba bean-based substrates. A total of 39 models were found and verified. The majority of these models indicate a strong impact of the temperature on the reduction of aldehydes connected to the "beany" impression (e.g., hexanal) and on the production of pleasantly perceived aroma compounds (e.g., β-damascenone). Positively, the addition of methionine had only minor impacts on the negatively associated sulfuric compounds methional, dimethyl sulfide, dimethyl disulfide, and dimethyl trisulfide. Moreover, in further fermentations, the time was added as an additional parameter. It was shown that the strains grew well, strongly acidified the both substrates (pH ≤ 4.0) within 6.5 h, and reached cell counts of > 9 log 10 CFU/mL after 24 h. Notably, most of the aldehydes (like hexanal) were reduced within the first 6-7 h, whereas pleasant compounds like β-damascenone reached high concentrations especially in the later fermentation (approx. 24-48 h)., Conclusions: Out of the fermentation parameters temperature, inoculum cell concentration, and methionine addition, the temperature had the highest influence on the observed aroma and taste active compounds. As the addition of methionine to compensate for the legume-typical deficit did not lead to an adverse effect, fortifying legume-based substrates with methionine should be considered to improve the bioavailability of the legume protein. Aldehydes, which are associated with the "beany" aroma impression, can be removed efficiently in fermentation. However, terminating the process prematurely would lead to an incomplete production of pleasant aroma compounds., (© 2024. The Author(s).)

To enhance the value of surimi, efforts have been made to develop a fermentation method with lactic acid bacteria (LAB) to proteolyze fish protein. However, fermenting unheated surimi poses a spoilage risk due to its high bacterial content. Surimi heat treatment can prevent spoilage, but gel formation induced by heating introduces another technical issue: it hinders uniform fermentation. Thus, this study aims to observe the proteolysis and enhance the functionality of seafood product through lactic acid fermentation of kamaboko, a heated surimi. Upon analyzing the kamaboko fermented with Lactobacillus helveticus JCM1004, we observed that LAB produced protease, resulting in the degradation of myosin heavy chain and actin during fermentation. Lactic acid fermentation significantly augmented the peptide content of kamaboko, subsequently elevating the angiotensin Ⅰ-converting enzyme (ACE) inhibitory activity in 200-fold diluted extract of fermented kamaboko to approximately 70% and higher. Notably, our investigation revealed that proteolysis was confined to the surface of kamaboko, as evidenced by SDS-PAGE analysis. This observation implies that the surface area of kamaboko influences the ACE inhibitory activity. Through a comparative analysis of various bacterial strains, we demonstrated that the increase in ACE inhibitory activity is contingent on the protease generated by LAB. These results suggest that LAB-mediated proteolysis of fish proteins liberates bioactive peptides, thereby manifesting in the ACE inhibitory activity. In summary, this study underscores that the fermentation of kamaboko employing proteolytic LAB holds promise in the development of novel functional seafood products.

The synthetic community of lactic acid bacteria (LAB) is commonly utilized in the food industry for manipulating product properties. However, the intermediate interactions and ecological stability resulting from metabolic differences among various LAB types remain poorly understood. We aimed to analyze the metabolic behavior of single and combined lactic acid bacteria in China rice wine based on microbial succession. Three-stage succession patterns with obligate heterofermentative LAB dominating prefermentation and homofermentative LAB prevailing in main fermentation were observed. Facultative heterofermentative LAB exhibited significant growth. Pairwise coculture interactions revealed 63.5% positive, 34.4% negative, and 2.1% neutral interactions, forming nontransitive and transitive competition modes. Nontransitive competitive combinations demonstrated stability over ∼200 generations through amino acid (mainly aspartic acid, glutamine, and serine) cross-feeding and lactic acid detoxification, which also showed potential for controlling biogenic amines and developing LAB starter cultures. Our findings offer insights into the mechanistic underpinnings of LAB interaction networks.

Spent coffee grounds (SCG) are commercial waste that are still rich in numerous valuable ingredients and can be further processed into useful products such as coffee oil, antioxidant extract, lactic acid, and lignin. The challenge and innovation is to develop the SCG processing technology, maximizing the use of raw material and minimizing the use of other resources within the sequential process. The presented research is focused on the aspect of biotechnological production of lactic acid from SCG by using the Lacticaseibacillus rhamnosus strain isolated from the environment. Thanks to the optimization of the processes of acid hydrolysis, neutralization, enzymatic hydrolysis of SCG, and fermentation, the obtained concentration of lactic acid was increased after 72 hr of culture from the initial 4.60 g/l to 48.6 g/l. In addition, the whole process has been improved, taking into account the dependence on other processes within the complete SCG biorefinery, economy, energy, and waste aspects. Costly enzymatic hydrolysis was completely eliminated, and it was proven that supplementation of SCG hydrolysate with expensive yeast extract can be replaced by cheap waste from the agri-food industry., One-Sentence Summary: A process for efficient lactic acid production from spent coffee grounds using the Lacticaseibacillus rhamnosus strain was developed and optimized, including nutrient solution preparation, supplementation and fermentation., (© The Author(s) 2024. Published by Oxford University Press on behalf of Society of Industrial Microbiology and Biotechnology.)

Lactic acid bacteria (LAB) fermented foods are reported to have potential in managing glycemic control. This systematic review aimed to evaluate the effectiveness of LAB-fermented foods on improving glycemic control in adults with prediabetics or type 2 diabetes mellitus (T2DM). Randomized controlled trials (RCTs) on LAB fermentation-related foods were searched on PubMed, Cochrane, Excerpta Medica database (EMBASE), Cumulative Index to Nursing and Allied Health Literature (CINAHL), and Web of Science. Sixteen RCTs were included, and the results concluded LAB-fermented food had significant effects in HbA1c ( Z  = 6.24, MD = -0.05, CI: -0.07 to -0.04, p  ≤ 0.00001), fasting plasma glucose ( Z  = 2.50, MD = -0.16, CI: -0.29 to -0.04, p  = 0.01) and fasting serum insulin ( Z  = 2.51, MD = -0.20, CI: -0.35 to -0.04, p  = 0.01). There were significant effects on lipid profile, inflammatory markers, and body mass index in secondary analyses. Subgroup analysis suggests LAB-fermented consumption with a longer duration, younger age group and adults with T2DM, had a larger effect size. Clinicians could offer LAB-fermented food as dietary recommendations for prediabetic and diabetic adults. Larger trials are warranted to verify LAB-fermented food benefits on glycemic control. Systematic Review Registration: PROSPERO Registration No. CRD42022295220.

Background: Lactic acid is one of the most important organic acids, with various applications in the food, beverage, pharmaceutical, cosmetic, and chemical industries. Optically pure forms of L- and D-lactic acid produced via microbial fermentation play an important role in the synthesis of biodegradable polylactic acid. Alternative substrates, including by-products and residues from the agro-food industry, provide a cost-effective solution for lactic acid production and are a promising avenue for the circular economy., Results: In this study, the transcription factor (TF)-based whole-cell biosensor strategy was developed for the L- and D-lactic acid determination. It was cross validated with commonly used high-performance liquid chromatography and enzymatic methods. The utility of biosensors as an efficient analytical tool was demonstrated by their application for the lactic acid determination and fermentation improvement. We explored the ability of Lacticaseibacillus paracasei subsp. paracasei, Lactobacillus delbrueckii subsp. lactis, and Lactobacillus amylovorus to biosynthesize optically pure L-lactic acid, D-lactic acid or mixture of both from organic-rich residual fraction (ORRF), a waste of glucose syrup production from wheat starch. The fermentation of this complex industrial waste allowed the production of lactic acid without additional pretreatment obtaining yields from 0.5 to 0.9 Cmol/Cmol glucose., Conclusions: This study highlights the utility of whole cell biosensors for the determination of L- and D-forms of lactic acid. The fermentation of L-lactic acid, D-lactic acid and mixture of both by L. paracasei, L. lactis, and L. amylovorus, respectively, was demonstrated using waste of glucose syrup production, the ORRF., (© 2023. The Author(s).)

D-Lactic acid is a chiral, three-carbon organic acid, that bolsters the thermostability of polylactic acid. In this study, we developed a microbial production platform for the high-titer production of D-lactic acid. We screened 600 isolates of lactic acid bacteria (LAB) and identified twelve strains that exclusively produced D-lactic acid in high titers. Of these strains, Lactobacillus saerimneri TBRC 5746 was selected for further development because of its homofermentative metabolism. We investigated the effects of high temperature and the use of cheap, renewable carbon sources on lactic acid production and observed a titer of 99.4 g/L and a yield of 0.90 g/g glucose (90% of the theoretical yield). However, we also observed L-lactic acid production, which reduced the product's optical purity. We then used CRISPR/dCas9-assisted transcriptional repression to repress the two Lldh genes in the genome of L. saerimneri TBRC 5746, resulting in a 38% increase in D-lactic acid production and an improvement in optical purity. This is the first demonstration of CRISPR/dCas9-assisted transcriptional repression in this microbial host and represents progress toward efficient microbial production of D-lactic acid., (© 2023. The Author(s), under exclusive licence to Microbiological Society of Korea.)

To combat the shortage of single agro-residue and overcome the problem of seasonal availability, it is beneficial to use mixture of lignocellulosic biomasses. In the present study, efforts were made to use mixed lignocellulosic biomass for production of bioethanol, along with microbial lipids and lactic acid. Upon enzymatic hydrolysis of mixed biomass at varied proportions it was observed that mixture of paddy straw and jute in the ratio 3:1 resulted in best sugar yield (41.50 g/L) at 10% substrate loading. Ethanolic fermentation of mixed substrate hydrolysate by thermotolerant yeast, Saccharomyces cerevisiae JRC6 resulted in 8.39 g/L of ethanol. To maintain sustainability and economic impact, oleaginous yeast ( Trichosporon mycotoxinivorans S2) and lactic acid bacteria ( Lactobacillus plantarum LP-9) were used for lipid production (14.5 g/L) and lactic acid production (11.08 g/L), respectively. Therefore, this study explored the potential of mixed lignocellulosic biomass to be exploited for production of various value-added products.

Enterococcus faecalis strain DB-5 is a lactic acid bacterium newly isolated from the Japanese mandarin orange (mikan). The DB-5 strain produces organic acid from various carbohydrate sources including glycerol and starch. To gain deeper insights into its potential application in lactic acid fermentation (LAF), the genome and fermentation analyses of E. faecalis DB-5 were performed. Whole genome sequencing was carried out using the DNBSEQ platform. After trimming and assembly, the total size of the assembled genome was revealed to be 3,048,630 bp, distributed into 63 contigs with an N 50 value of 203,673. The genome has 37.2% GC content, 2928 coding DNA sequences, and 54 putative RNA genes. The DB-5 strain harbored two l-lactate dehydrogenases (L-LDHs), both of which conserved the catalytic domain sequences. The optical purity measurement showed that strain DB-5 is homofermentative and produced only l-lactic acid (LA), which correlated with genome-based pathway analysis. To confirm its LA productivity at high temperatures, open repeated batch fermentation was performed at 45 °C using sucrose as a carbon source. The volumetric LA productivity of DB-5 was averaged at 3.66 g L -1  h -1 for 24 h during the 3rd to 11th fermentation cycles. E. faecalis DB-5 could efficiently convert around 94% of sucrose to LA throughout the fermentation cycles at 45 °C. These genomic characteristics and fermentation properties of E. faecalis DB-5 provide beneficial information for a deeper understanding of the functional properties of future high-temperature LAFs from biomass resources., (Copyright © 2023 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.)

To substitute petroleum-based materials with bio-based alternatives, microbial fermentation combined with inexpensive biomass is suggested. In this study Saccharina latissima hydrolysate, candy-factory waste, and digestate from full-scale biogas plant were explored as substrates for lactic acid production. The lactic acid bacteria Enterococcus faecium, Lactobacillus plantarum, and Pediococcus pentosaceus were tested as starter cultures. Sugars released from seaweed hydrolysate and candy-waste were successfully utilized by the studied bacterial strains. Additionally, seaweed hydrolysate and digestate served as nutrient supplements supporting microbial fermentation. According to the highest achieved relative lactic acid production, a scaled-up co-fermentation of candy-waste and digestate was performed. Lactic acid reached a concentration of 65.65 g/L, with 61.69% relative lactic acid production, and 1.37 g/L/hour productivity. The findings indicate that lactic acid can be successfully produced from low-cost industrial residues., Competing Interests: Declaration of Competing Interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Irini Angelidaki reports financial support was provided by Horizon Europe. The remaining authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

The detection of lactate is an important indicator of the freshness, stability, and storage stability of products as well as the degree of fermentation in the food industry. In addition, it can be used as a diagnostic tool in patients' healthcare since it is known that the lactate level in blood increases in some pathological conditions. Thus, the determination of lactate level plays an important role in not only the food industry but also in health fields. As a result, biosensor technologies, which are quick, cheap, and easy to use, have become important for lactate detection. In the current study, amperometric lactate biosensors based on lactate oxidase immobilization (with Nafion 5% wt) were designed and the limit of detection, linear range, and sensitivity values were determined to be 31 μM, 50-350 μM, and 0.04 μA μM -1  cm -2 , respectively. Then, it was used for the measurement of lactic acid that produced by six different and morphologically identified presumptive lactic acid bacteria (LAB) which are isolated from different naturally fermented cheese samples. The biosensors were then used to successfully perform lactate measurements within 3 min for each sample, even though a few of them were out of the limit of detection. Thus, electrochemical biosensors should be used as an alternative and quick solutions for the measurement of lactate metabolites rather than the traditional methods which require long working hours. This is the first study to use a biosensor to measure lactate produced by foodborne LAB in a real sample., (Copyright © 2023 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.)

Two lactic acid bacterial strains (IMAU80584 T and IMAU92037) were isolated from naturally fermented dairy products (kurut and yoghurt) in China and Russia. Based on sequence analysis of the 16S rRNA gene it was revealed that these strains belonged to Lentilactobacillus rapi . However, phylogenetic tree analyses of two housekeeping genes, rpoA (encoding RNA polymerase alpha subunit) and pheS (encoding phenylalanyl-tRNA synthase alpha subunit), and 88 core genes, indicated the two strains were separated into an independent monophyletic branch from L. rapi DSM 19907 T , forming an infra-specific subgroup. The average nucleotide identity and digital DNA-DNA hybridization values between IMAU80584 T and L. rapi DSM 19907 T were 93.1 and 52.8 %, respectively. Strains IMAU80584 T and IMAU92037 are distinguished from L. rapi DSM 19907 T because they have different polar lipids and fatty acids. The novel subgroup strains could not ferment gluconate potassium. The DNA G+C content of strain IMAU80584 T was 42.3 mol%. The major cellular fatty acids were C 16 : 0 , C 18 : 1  ω 9t and summed feature 5 (C 18 : 0 ante and/or C 18 : 2  ω 6 c and/or C 18 : 2  ω 9c). Therefore, based on the results of polyphasic taxonomic analysis, IMAU80584 T and IMAU92037 could be considered as a novel subspecies in the species L. rapi with the proposed name Lentilactobacillus rapi subsp. dabitei subsp. nov. The type strain is IMAU80584 T (=GDMCC 1.2566 T =JCM 34647 T ).

Polypropylene was modified to contain chitosan and evaluate its ability to generate Lactobacillus casei biofilms and their lactic acid production. Biofilm formation was carried out in either rich or minimal media. The chitosan-modified polypropylene harbored ~ 37% more cells than the control polypropylene. The biofilms from the chitosan-modified polypropylene grown in rich medium produced ~ 2 times more lactic acid after 72 h of incubation than the control suspended cells. There was no significant difference in the production of lactic acid after 72 h by L. casei biofilms on the chitosan-modified polypropylene grown in minimal media as compared with cells in suspension after 48 h and 72 h of incubation. Infrared spectroscopy confirmed higher deposition of nutrients and biomass on the chitosan-modified polypropylene as compared to the chitosan-free polypropylene. Electron and atomic force microscopy confirmed thicker biofilms when rich media were used to grow them as compared to minimal medium., (© 2021. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

This work was carried out to elaborate selenium (Se) bio-enriched fermented Mediterranean fruit juices. To this purpose, pomegranate and table red grape juices were added with sodium selenite (Na 2 SeO 3 ) and fermented by Levilactobacillus brevis CRL 2051 and Fructobacillus tropaeoli CRL 2034 individually or combined. To better evaluate the effect of selenite addition and starter strain inoculums on the total bacterial community of the fruit juices, fermentation trials were performed with raw and pasteurized fruit juices. No statistical significant differences were observed for total mesophilic microorganisms (TMM) and rod-shaped lactic acid bacteria (LAB) levels among raw and pasteurized juices inoculated with the starter strains, while significant differences between those juices with and without selenite were registered. LAB cocci, Pseudomonadaceae and yeasts were detected only for the raw juice preparations. The dominance of L. brevis CRL 2051 and F. tropaeoli CRL 2034 was confirmed by randomly amplified polymorphic DNA (RAPD)-PCR analysis. After fermentation, pH dropped for all inoculated trials and control raw juices. The soluble solid content (SSC) levels of the raw juices were higher than the corresponding pasteurized trials. The thermal treatment affected consistently yellowness of grape juice trials and redness of pomegranate juices. No microbial Se accumulation was registered for pomegranate juices, while F. tropaeoli CRL 2034 accumulated the highest amount of Se (65.5 μg/L) in the grape juice. For this reason, only trials carried out with raw grape juices were investigated by metagenomics analysis by Illumina MiSeq technology. Non-inoculated grape juices were massively fermented by acetic acid bacteria while Fructobacillus and Lactobacillus (previous genus name of Levilactobacillus) represented the highest operational taxonomy units (OTUs) relative abundance % of the trials inoculated with the starter strains as confirmed by this technique., (Copyright © 2021 Elsevier B.V. All rights reserved.)

Spent sulfite liquor (SSL), a waste stream from wood pulp production, has great potential as carbon source for future industrial fermentations. In the present study, SSL was separated into a hemicellulose derived sugar syrup (HDSS) and a lignosulfonic fraction by simulated moving bed chromatography. The recovery of SSL sugars in the HDSS was 89% and the fermentation inhibitors furfural, 5-hydroxymethylfurfural and acetic acid were removed by 98.7%, 60.5% and 75.5%, respectively. The obtained sugars have been converted to L-lactic acid, a building block for bioplastics, by fermentation with the lactic acid bacterium Enterococcus mundtii DSM4838. Batch fermentations on HDSS produced up to 56.3 g/L L-lactic acid. Simultaneous conversion of pentose and hexose sugars during fed-batch fermentation of wildtype E. mundtii led to 87.9 g/L optically pure (>99%) L-lactic acid, with maximum productivities of 3.25 g/L.h and yields approaching 1.00 g/g during feeding phase from HDSS as carbon source., (Copyright © 2021 The Author(s). Published by Elsevier Ltd.. All rights reserved.)

Inoculation of sourdough allows the fermentation medium to be dominated by desired microorganisms, which enables determining the kinetics of the conversion of chemical compounds by individual microorganisms. This knowledge may allow the design of functional food products with health features dedicated to consumers with special needs. The aim of the study was to assess the dynamics of transformations of fermentable oligosaccharide, disaccharide, monosaccharide and polyol (FODMAP) compounds from wheat flour as well as their antioxidant activity during inoculated and spontaneous sourdough fermentation. The FODMAP content in grain products was determined by the fructan content with negligible amounts of sugars and polyols. To produce a low-FODMAP cereal product, the fermentation time is essential. The 72 h fermentation time of L. plantarum -inoculated sourdough reduced the FODMAP content by 91%. The sourdough fermentation time of at least 72 h also positively influenced the content of polyphenols and antioxidant activity, regardless of the type of fermentation. The inoculation of both L. plantarum and L. casei contributed to a similar degree to the reduction in FODMAP in sourdough compared to spontaneous fermentation.

Dark fermentation (DF) is one of the most promising biological methods to produce bio-hydrogen and other value added bio-products from carbohydrate-rich wastes and wastewater. However, process instability and low hydrogen production yields and rates have been highlighted as the major bottlenecks preventing further development. Numerous studies have associated such concerns with the inhibitory activity of lactate-producing bacteria (LAB) against hydrogen producers. However, an increasing number of studies have also shown lactate-based metabolic pathways as the prevailing platform for hydrogen production. This opens a vast potential to develop new strategies to deal with the "Achilles heel" of DF - LAB overgrowth - while untapping high-performance DF. This review discusses the key factors influencing the lactate-driven hydrogen production, paying particular attention to substrate composition, the operating conditions, as well as the microbiota involved in the process and its potential functionality and related biochemical routes. The current limitations and future perspectives in the field are also presented., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

Lactate production in anaerobic carbohydrate fermentations with mixed cultures of microorganisms is generally observed only in very specific conditions: the reactor should be run discontinuously and peptides and B vitamins must be present in the culture medium as lactic acid bacteria (LAB) are typically auxotrophic for amino acids. State-of-the-art anaerobic fermentation models assume that microorganisms optimise the adenosine triphosphate (ATP) yield on substrate and therefore they do not predict the less ATP efficient lactate production, which limits their application for designing lactate production in mixed-culture fermentations. In this study, a metabolic model taking into account cellular resource allocation and limitation is proposed to predict and analyse under which conditions lactate production from glucose can be beneficial for microorganisms. The model uses a flux balances analysis approach incorporating additional constraints from the resource allocation theory and simulates glucose fermentation in a continuous reactor. This approach predicts lactate production is predicted at high dilution rates, provided that amino acids are in the culture medium. In minimal medium and lower dilution rates, mostly butyrate and no lactate is predicted. Auxotrophy for amino acids of LAB is identified to provide a competitive advantage in rich media because less resources need to be allocated for anabolic machinery and higher specific growth rates can be achieved. The Matlab™ codes required for performing the simulations presented in this study are available at https://doi.org/10.5281/zenodo.4031144., (© 2020 Wiley Periodicals LLC.)

Aerobic fed-batch cultures were studied as a means of suppressing the production of lactate, which inhibits the growth of lactic acid bacteria (LAB). LAB produce lactate via lactate dehydrogenase (LDH), regenerating nicotinamide adenine dinucleotide (NAD + ) consumed during glycolysis. Therefore, we focused on NADH oxidase (NOX), employing oxygen as an electron acceptor, as an alternative pathway to LDH for NAD + regeneration. To avoid glucose repression of NOX and NAD + consumption by glycolysis exceeding NAD + regeneration by NOX, glucose was fed gradually. When Lactococcus lactis MG 1363 was aerobically fed at a specific growth rate of 0.2 h -1 , the amount of lactate produced per amount of grown cell was reduced to 12% of that in anaerobic batch cultures. Metabolic flux analysis revealed that in addition to NAD + regeneration by NOX, ATP acquisition by production of acetate and NAD + regeneration by production of acetoin and 2,3-butanediol contributed to suppression of lactate production., (Copyright © 2020 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.)

This study was aimed to evaluate the effectiveness of two lactic acid bacteria (LAB) cultures (Lactococcus lactis FT27 and Carnobacteroim divergens SCA), lactic acid/sodium lactate (LASL - l-lactic acid 61% (w/w) and L-sodium lactate 21% (w/w)) and their combination against four Listeria monocytogenes biotypes isolated from Gorgonzola cheese. In vitro antilisterial activity showed that the sensitivity to antimicrobials was strain-dependent. Antimicrobial challenge testing was performed on Gorgonzola rinds simulating contamination occurring at the beginning (6 days) and at the end (55 days) of the ripening period, to assess the antilisterial activity of LAB strains and LASL during the subsequent 60 days at 4 °C. LASL showed a higher antilisterial activity than LAB, maintaining the pathogen content below the EC limit (<2.0 log 10  CFU/g) for 60 days. A strong listericidal effect was observed combining LAB with LASL (2,8 μL/cm 2 ) Lc. lactis in combination with LASL completely inhibited the two L. monocytogenes strains in the first 50 days, while LASL with C. divergens was more effective in the second part of ripening when the pH raised. Data obtained encourage the use of LASL along with antimicrobial LAB rotation schemes during cheese ripening for the prevention and/or control of the L. monocytogenes on cheese surface., Competing Interests: Declaration of competing interest All the authors declare no conflict of interest in this paper., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

Lactic acid bacteria (LAB) is mainly used in food fermentation. In addition, LAB fermentation technology has been studied in the development of industrial food additives, nutrients, or enzymes used in food processing. In the field of red biotechnology, LAB is approved and is generally recognized as a safe organism and is considered safe for biotherapeutic treatments. Recent clinical trials have demonstrated the medicinal value of therapeutic recombinant LAB and the suitability of innate mechanisms of secretion and anchoring for therapeutic applications such as antibody or vaccine production. However, the gram-positive phenotypic trait of LAB creates challenges for genetic modifications when compared to other conventional workhorse bacteria, resulting in exclusive developments of genetic tools for engineering LAB. In this review, several distinct approaches in gene expression for engineering LAB are discussed., (© 2020 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

We report a method for suppression of lactate production by lactic acid bacteria (LAB) in culture. LAB produce lactate to regenerate NAD + that is consumed during glycolysis. Glucose suppresses NAD + regeneration pathways other than lactate dehydrogenase and non-glycolytic ATP production pathways. Therefore, the carbon source was changed to sucrose, and fed-batch culture was performed to limit the glycolytic flux and thus suppress lactate production. As a result, lactate productivity (i.e., the amount of lactate produced per amount of grown cell) in the sucrose/fed-batch culture was decreased compared to that in glucose/batch culture, in all five LAB strains examined. The productivity level decreased to 24% and 46% in Lactobacillus reuteri JCM 1112 and Lactococcus lactis JCM 7638, respectively. Metabolic flux analysis of Lactobacillus reuteri JCM 1112 revealed increased contributions of the mannitol production pathway to NAD + regeneration and the arginine deiminase pathway to ATP production in the sucrose/fed-batch culture., (Copyright © 2019 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.)

Grains are a substantial source of macronutrients and energy for humans. Lactic acid (LA) fermentation is the oldest and most popular way to improve the functionality, nutritional value, taste, appearance and safety of cereal foods and reduce the energy required for cooking. This literature review discusses lactic acid fermentation of the most commonly used cereals and pseudocereals by examination of the microbiological and biochemical fundamentals of the process. The study provides a critical overview of the indispensable participation of lactic acid bacteria (LAB) in the production of many traditional, ethnic, ancient and modern fermented cereals and beverages, as the analysed literature covers 40 years. The results reveal that the functional aspects of LAB fermented foods are due to significant molecular changes in macronutrients during LA fermentation. Through the action of a vast microbial enzymatic pool, LAB form a broad spectrum of volatile compounds, bioactive peptides and oligosaccharides with prebiotic potential. Modern applications of this ancient bioprocess include the industrial production of probiotic sourdough, fortified pasta, cereal beverages and "boutique" pseudocereal bread. These goods are very promising in broadening the daily menu of consumers with special nutritional needs.

Lactic acid bacteria are beneficial to human health. Lactic acid bacteria have wide applications in food, cosmetic and medicine industries due to being Generally Recognized As Safe (GRAS) and a multitude of therapeutic and functional properties. Previous studies have reported the beneficial effects of lactic acid bacteria, their extracts or ferments on skin health, including improvements in skin conditions and the prevention of skin diseases. Lipoteichoic acid isolated from Lactobacillus plantarum was reported to inhibit melanogenesis in B16F10 melanoma cells. In particular, lipoteichoic acid also exerted anti-photoaging effects on human skin cells by regulating the expression of matrix metalloproteinase- 1. The oral administration of Lactobacillus delbrueckii and other lactic acid bacteria has been reported to inhibit the development of atopic diseases. Additionally, the clinical and histologic evidence indicates that the topical application of lactic acid is effective for depigmentation and improving the surface roughness and mild wrinkling of the skin caused by environmental photo-damage. This review discusses recent findings on the effects of lactic acid bacteria on skin health and their specific applications in skin-whitening cosmetics., (Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.net.)

Lactate produced by lactic acid bacteria inhibits their growth. To suppress lactate production, it is necessary to regenerate NAD + consumed by glycolysis with alternative pathways other than lactate dehydrogenase. In a heterofermentative lactic acid bacterium, Lactobacillus reuteri JCM1112, suppression of lactate production by regenerating NAD + when producing 1,3-propanediol from glycerol was investigated. The bacterium produced lactate with a yield of 4.7 ± 0.8 g·g-cell -1 in a batch culture using glucose as the sole carbon source. When glycerol was added to glucose at a molar ratio (r Gly/Glc ) of three in the batch culture, the bacterium produced 1,3-propanediol at 1.6 ± 0.7 g·g-cell -1 ·h -1 and the lactate yield decreased to 3.6 ± 0.5 g·g-cell -1 . When glycerol was co-fed with glucose exponentially to give a target specific growth rate of 0.1 h -1 (r Gly/Glc  = 3), the lactate yield decreased to 1.5 ± 0.2 g·g-cell -1 . The lactate production when glycerol was added together with glucose was reduced to one-third of that observed in the batch culture using glucose as a carbon source., (Copyright © 2019 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.)

The present study aimed to assess the palatability of sausages undergoing low-temperature fermentation and drying process. Lactobacillus sakei D-1001 or Lactobacillus salivarius A001 were used as starter cultures for fermentation, and the following properties of the sausages were investigated: colony-forming units of lactic acid bacteria; concentrations of lactic acid, protein, peptides, and free amino acids; distribution of protein; composition of free amino acids; and physical properties and taste. Alterations in the composition of proteins, peptides, and free amino acids as well as in various physical properties were caused by fermentation by lactic acid bacteria. A sensory test indicated that the palatability of the fermented sausages was greater than that of the non-fermented sausages, particularly in terms of hardness and juiciness. This was considered to be due to protein degeneration and changes in the physical properties of the sausages as a result of fermentation by lactic acid bacteria. However, the taste of the fermented sausages was sourer than that of the non-fermented sausages, and therefore, inferior. Our study revealed that the palatability of the sausages in terms of hardness and juiciness were increased by low-temperature fermentation by lactic acid bacteria and the drying process., (© 2020 Japanese Society of Animal Science.)

Although most lactic acid bacteria do not directly incorporate purine nucleotides, the strain Lactobacillus gasseri PA-3 was found to incorporate purine mononucleotides. To determine whether the direct uptake of purine mononucleotides is dependent on the species or strain of lactic acid bacteria, incorporation of purine mononucleotides was assessed in L. gasseri , Lactcoccus lactis sbsp. lactis and other species of lactic acid bacteria. Each bacterial strain was incubated with , Streptococcus thermophilus and other species of lactic acid bacteria. Each bacterial strain was incubated with 32 P-AMP or 14 C-adenosine and the incorporation of each purine was evaluated by measuring their radioactivity. All investigated strains of L. gasseri incorporated 32 P-AMP, whereas strains of S. thermophilus and most strains of L. lactis did not. Incorporation of 32 P-AMP into strains of Pediococcus was dependent on the strain or species of that genus of bacteria. All investigated strains, except for one strain of L. gasseri , incorporated 14 C-adenosine, with S. thermophilus , L. lactis and Pediococcus generally displaying greater incorporation of 14 . Although most lactic acid bacteria such as L. gasseri . Although most lactic acid bacteria such as S. thermophiles and L. lactis directly incorporate purine mononucleotides. These findings indicate that the preferential incorporation of purine mononucleotides or nucleosides by lactic acid bacteria is dependent on the species or strain.L. gasseri directly incorporate purine mononucleotides. These findings indicate that the preferential incorporation of purine mononucleotides or nucleosides by lactic acid bacteria is dependent on the species or strain.

Lactic acid bacteria (LAB) grow by producing lactate from sugar. However, the accumulation of lactate inhibits their growth. Here, the lactate productivity per cell in a semi-solid medium prepared with a chlorella powder in several LAB strains was much lower than that in the conventional MRS medium. Furthermore, the lactate production was suppressed not only in semi-solid medium, but also in chlorella liquid medium. The lactate productivity by Lactococcus lactis subsp. lactis NBRC 12007 in the chlorella liquid medium and MRS medium was 3.0 and 6.9 g-lactate·g-cell -1 , respectively. The productivity of lactate in the chlorella liquid medium decreased to 44% of that in MRS medium. Gas chromatography/mass spectrometry (GC/MS) analysis of the culture supernatants revealed that the utilization of sucrose in the chlorella powder led to the suppression of lactate production. Comparison of the metabolites extracted from the cells indicated that the two ATP generating pathways, the arginine deiminase pathway and the decarboxylation reaction of glutamate and GABA, which are usually repressed by glucose, are activated in chlorella medium. It was considered that these pathways which do not require NAD + for generation of ATP are not repressed when sucrose is used as a carbon source. Thus, the utilization of these pathways results in the suppression of the lactate production., (Copyright © 2019 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.)

Lactic acid (LA) is one of the most desired molecules by the chemical industry. Current expansion of LA market is mainly driven by its application as building block for the synthesis of polylactide (PLA), that is, a family of biodegradable and biocompatible plastic polymers. PLA can potentially replace oil-derived polymers as general purpose plastic, but current LA prices fails to make PLA cost-competitive with traditional plastics. Nowadays, LA is mainly produced by fermentation of expensive starchy biomass. Hopefully, cheaper lignocellulosic feedstock could be used in future second-generation biorefinery processes. However, most efficient natural LA producers cannot ferment lignocellulose without prior biomass saccharification. Metabolic engineering may develop improved microorganisms that feature both efficient biomass hydrolysis and LA production, thus supporting consolidated bioprocessing (CBP), that is, one-pot fermentation, of lignocellulose to LA. CBP could dramatically reduce LA production cost, thus contributing to the expansion of more environmental sustainable plastics and commodity chemicals. This review presents an overview of "recombinant cellulolytic strategies", mainly consisting in introducing cellulase systems in native producers of LA, and "native cellulolytic strategies" aimed at improving LA production in natural cellulolytic microorganisms. Issues and perspectives of these approaches will be discussed., (© 2019 International Union of Biochemistry and Molecular Biology, Inc.)

Background: Considering the large amounts of by-products derived from orange processing, which are generally discarded, the present study aimed to explore the feasibility of using orange peel for lactic acid production in solid state fermentation., Results: Different species of lactic acid bacteria were employed, singly and in co-culture, to evaluate their ability to ferment orange peel and produce lactic acid. Among the single cultures tested, Lactobacillus casei 2246 was the most efficient strain, reaching the highest concentration of lactic acid (209.65 g kg -1 ) and yield (0.88 g g -1 ). The use of Lactobacillus plantarum 285 and Lactobacillus paracasei 4186 in co-culture produced a comparable amount of lactic acid, showing a better performance than the same strains in single cultures., Conclusion: Orange peels represent a suitable raw material for solid state fermentation employing lactic acid bacteria. Lactic acid was obtained that consumed the most of sugars available, leading to high yields. Despite all the strains tested showing the same growth ability, different peculiarities in lactic acid production were revealed, dependent on the species/strains, suggesting the relevance of strain selection. © 2019 Society of Chemical Industry., (© 2019 Society of Chemical Industry.)

The aim of this work was to study the metabolic and microbial community dynamics during dark co-fermentation of 80% tequila vinasse and 20% nixtamalization wastewater (w/w). Batch co-fermentations were performed in a 3-L well-mixed reactor at 35 °C and pH 5.5. In correspondence to Illumina MiSeq sequencing and reactor monitoring, changes in metabolites and microbial communities were characterized by three main stages: (i) a first stage during which lactate and acetate producers dominated and consumed the major part of fermentable carbohydrates, (ii) a second stage in which lactate and acetate were consumed by emerging hydrogen-producing bacteria (HPB) in correlation with bioH 2 (100 NmL/L-h or 1200 NmL/L reactor ) and butyrate production, and (iii) a third stage during which non-HPB outcompeted HPB after bioH 2 production ceased. Altogether, the results of this study suggest that cooperative interactions between lactate producers and lactate- and acetate-consuming HPB could be attributed to lactate- and acetate-based cross-feeding interactions., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

Ensiling is one of the best known method to preserve fodder. The forage before ensiling intended for silages usually contains a low number of lactic acid bacteria (LAB), so it is necessary to apply starter cultures of selected strains. Traditionally, LAB starter cultures were applied to lower the pH by producing lactic acid and to inhibit the growth of undesirable epiphytic microorganisms by competing for nutrients. Nowadays, LAB inoculants have become an effective tool for creating microbial quality of silages by selecting species with extraordinary features. Epiphytic microflora characteristic of plant material used for the production of silages and the sources of undesirable microflora in the ensiling process are discussed. This review focuses on the most frequently studied issues related to the microbial silage quality and the recent trends in increasing the quality by LAB inoculants, with respect to recent directions for selecting types of modern LAB for inoculation. Among them, the main trends described were prevention of the growth of filamentous fungi and detoxification of mycotoxins by LAB inoculants, inhibition of yeast growth by LAB present in preparations and limiting the development of pathogenic bacterial microflora through controlled fermentation with the participation of LAB and the presence of their metabolites.

This study investigated the effects of lactic acid bacteria on bacterial and fungal community during the fermentation process and aerobic exposure phase of barley ensiled with preparation of lactic acid bacteria (LAB). The inoculated silages displayed higher contents of lactic acid, acetic acid, and propionic acid as well as a greater number of lactic acid bacteria during ensiling. LAB-treated silage decreased the bacterial diversity during both ensiling and aerobic exposure but increased the fungal diversity during ensiling of barley. LAB-treated silage during ensiling increased the abundance of Lactobacillus but decreased that of Weissella. After aerobic exposure, LAB-treated silage increased the abundance of Lactobacillus but decreased that of Acinetobacter. Acinetobacter, Enterococcus, Providencia, and Empedobacter were the dominant bacteria after aerobic exposure. In conclusion, LAB-treated silage enhanced the number of desirable Lactobacillus and inhibited the growth of undesirable microorganisms, such as Acinetobacter., (Copyright © 2018. Published by Elsevier Ltd.)

In this study, a lactate-type fermentation entailing the consumption of lactate and acetate (lactate-acetate pathway) is proposed to deal with lactic acid bacteria (LAB) inhibition during the production of biohydrogen (bioH 2 ) from tequila vinasse. The effects of total solids content, substrate concentration, nutrient formulation and inoculum addition on bioH 2 production performance were investigated. Batch experiments were performed in a 3-L completely mixed reactor at 35 °C and pH 6.5-5.8. The lactate-acetate pathway mediated consistent bioH 2 production which was influenced by inoculum addition followed by substrate concentration, nutrient formulation and solids content. Maximum bioH 2 production rate (225 NmL/L-h) and yield (124 NmL/g VS added ) were achieved by removing suspended solids and enhancing nutrient content, respectively. Illumina sequencing-based analysis revealed a dominance of Clostridium in the inoculum, which together with LAB and acetic acid bacteria shaped a keystone cluster for avoiding LAB inhibition while ensuring consistent bioH 2 production performance., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

Lactic acid is a versatile chemical that can be produced via fermentation of lignocellulosic materials. The heterolactic strain Lactobacillus pentosus CECT 4023 T, that can consume glucose and xylose, was studied to produce lactic acid from steam exploded wheat straw prehydrolysate. The effect of temperature and pH on bacterial growth was analyzed. Besides, the effect of oxygen on lactic acid production was tested and fermentation yields were compared in different scenarios. This strain showed very high tolerance to the inhibitors contained in the wheat straw prehydrolysate. The highest lactic acid yields based on present sugar, around 0.80 g g -1 , were obtained from glucose in presence of 25%, 50%, and 75% v v -1 of prehydrolysate in strict anaerobiosis. Lactic fermentation of wheat straw hydrolysate obtained after enzymatic hydrolysis of the prehydrolysate yielded 0.39 g of lactic acid per gram of released sugars, which demonstrated the high potential of L. pentosus to produce lactic acid from hemicellulosic hydrolysates. Results presented herein not only corroborated the ability of L. pentosus to grow using mixtures of sugars, but also demonstrated the suitability of this strain to be applied as an efficient lactic acid producer in a lignocellulosic biorefinery approach. © 2018 American Institute of Chemical Engineers Biotechnol. Prog., 35: e2739, 2019., (© 2018 American Institute of Chemical Engineers.)

The microbiota of fresh French pork sausages were characterised in five batches of comminuted pork meat that were equally divided into two formulations either containing the acid-based preservatives lactate and acetate, or no preservatives. Conventional microbiological analysis and high-throughput 16S rDNA amplicon sequencing methods were performed on meat batches packed under modified atmosphere (70% oxygen and 30% carbon dioxide) during chilled storage. In addition, meat pH and colour, and gas composition of the packages were monitored until the end of the shelf-life. During storage, the population of mesophilic and lactic acid bacteria increased from 4 log CFU/g to 8 log CFU/g after 15 days of chilled storage, both with and without preservatives. Despite similar changes of the physical and chemical parameters, such as pH and package gas composition, spoilage was delayed in the meat containing the preservatives, suggesting that lactate and acetate are effective against spoilage. Metagenetic analysis showed that at the end of the shelf-life, the species distribution differed between both the formulations and the batches. Lactic acid bacteria were shown to dominate both with and without preservatives; however, samples containing no preservatives were characterised by the presence of an increased population of Brochothrix spp. and Pseudomonas spp. whereas, Leuconostoc mesenteroides/pseudomesenteroides and Lactobacillus curvatus/graminis were more abundant in the meat with preservatives., (Copyright © 2018. Published by Elsevier Ltd.)

Yeasts, lactic and acetic acid bacteria are responsible of microbial spoilage of alcoholic beverages. However species involved in deterioration of sorghum beer produced in Côte d'Ivoire has not been investigated. This study was carried out to identify species of yeast, LAB and AAB during spoilage of tchapalo in order to define the best strategy for beer preservative. Thus, a total of 210 yeasts, LAB and AAB were isolated from samples of tchapalo stored at ambient temperature and at 4 °C for 3 days. Based on PCR-RFLP of the ITS region and the sequencing of D1/D2 domain, yeast isolates were assigned to seven species (Saccharomyces cerevisiae, Candida tropicalis, Rhodotorula mucilaginosa, Trichosporon asahii, Kluyveromyces marxianus, Meyerozyma guilliermondii and Trichosporon coremiiforme). During the storage at ambient temperature and at 4 °C, S. cerevisiae was the predominant species (> 76%). Excepted R. mucilaginosa, occurrence of non-Saccharomyces species was sporadic. LAB species detected in fresh samples using molecular methods were Pediococcus acidilactici, Lactobacillus paracasei, Lb. curvatus, Lb. fermentum and Weisssella paramesenteroides. P. acidilactici was the dominant species (47.8%) followed by Lb. paracasei (17.5%). W. paramesenteroides and Lb. fermentum were not detected during the spoilage at ambient temperature while at 4 °C W. paramesenteroides and Lb. paracasei have not been detected. For AAB, the species found were Acetobacter pasteurianus sub paradoxus and Acetobacter cerevisiae. These species were common to all samples during spoilage and A. pasteurianus sub paradoxus was the most frequently detected.

Lactobacillus buchneri is a Gram-positive, obligate heterofermentative, facultative anaerobe commonly affiliated with spoilage of food products. Notably, L. buchneri is able to metabolize lactic acid into acetic acid and 1,2-propanediol. Although beneficial to the silage industry, this metabolic capability is detrimental to preservation of cucumbers by fermentation. The objective of this study was to characterize isolates of L. buchneri purified from both industrial and experimental fermented cucumber after the onset of secondary fermentation. Genotypic and phenotypic characterization included 16S rRNA sequencing, DiversiLab® rep-PCR, colony morphology, API 50 CH carbohydrate analysis, and ability to degrade lactic acid in modified MRS and fermented cucumber media. Distinct groups of isolates were identified with differing colony morphologies that varied in color (translucent white to opaque yellow), diameter (1 mm-11 mm), and shape (umbonate, flat, circular or irregular). Growth rates in MRS revealed strain differences, and a wide spectrum of carbon source utilization was observed. Some strains were able to ferment as many as 21 of 49 tested carbon sources, including inulin, fucose, gentiobiose, lactose, mannitol, potassium ketogluconate, saccharose, raffinose, galactose, and xylose, while others metabolized as few as eight carbohydrates as the sole source of carbon. All isolates degraded lactic acid in both fermented cucumber medium and modified MRS, but exhibited differences in the rate and extent of lactate degradation. Isolates clustered into eight distinct groups based on rep-PCR fingerprints with 20 of 36 of the isolates exhibiting >97% similarity. Although isolated from similar environmental niches, significant phenotypic and genotypic diversity was found among the L. buchneri cultures. A collection of unique L. buchneri strains was identified and characterized, providing the basis for further analysis of metabolic and genomic capabilities of this species to enable control of lactic acid degradation in fermented plant materials., (Published by Elsevier B.V.)

d-Lactate dehydrogenase (d-LDH) catalyzes the reversible reaction pyruvate + NADH + H + ↔ lactate + NAD + , which is a principal step in the production of d-lactate in lactic acid bacteria. In this study, we identified and characterized the major d-LDH (d-LDH1) from three d-LDHs in Leuconostoc mesenteroides, which has been extensively used in food processing. A molecular simulation study of d-LDH1 showed that the conformation changes during substrate binding. During catalysis, Tyr101 and Arg235 bind the substrates by hydrogen bonds and His296 acts as a general acid/base for proton transfer. These residues are also highly conserved and have coevolved. Point mutations proved that the substrate binding sites and catalytic site are crucial for enzyme activity. Network and phylogenetic analyses indicated that d-LDH1 and the homologues are widely distributed but are most abundant in bacteria and fungi. This study expands the understanding of the functions, catalytic mechanism, and evolution of d-LDH.

D-lactic acid is a versatile and important industrial chemical that can be applied in the synthesis of thermal-resistant poly-lactic acid. Biosynthesis of D-lactic acid can be achieved by a variety of microorganisms, including lactic acid bacteria, yeast, and fungi; however, the final product yield, optical purity, and the utilization of both glucose and xylose are restricted. Consequently, engineered microbial systems are essential to attain high titer, productivity, and complete utilization of sugars. Herein, we critically evaluate the promising wild-type microorganisms, as well as genetically modified microorganisms to produce enantiomerically pure D-lactic acid, particularly from renewable lignocellulosic biomass. In addition, innovative bioreactor operation, metabolic flux analysis, and recent genetic engineering methods for targeted microbial D-lactic acid synthesis will be discussed.

Lactic acid (LA) is an important platform chemical due to its significant applications in various fields and its use as a monomer for the production of biodegradable poly(lactic acid) (PLA). Free LA production is required to get rid of CaSO 4 , a waste material produced during fermentation at neutral pH which will lead to easy purification of LA required for the production of biodegradable PLA. Additionally, there is no need to use corrosive acids to release free LA from the calcium lactate produced during neutral fermentation. To date, several attempts have been made to improve the acid tolerance of lactic acid bacteria (LAB) by using both genome-shuffling approaches and rational design based on known mechanisms of LA tolerance and gene deletion in yeast strains. However, the lack of knowledge and the complexity of acid-tolerance mechanisms have made it challenging to generate LA-tolerant strains by simply modifying few target genes. Currently, adaptive evolution has proven an efficient strategy to improve the LA tolerance of individual/engineered strains. The main objectives of this article are to summarize the conventional biotechnological LA fermentation processes to date, assess their overall economic and environmental cost, and to introduce modern LA fermentation strategies for free LA production. In this review, we provide a broad overview of free LA fermentation processes using robust LAB that can ferment in acidic environments, the obstacles to these processes and their possible solutions, and the impact on future development of free LA fermentation processes commercially.

This study was conducted to investigate the effect of lactic acid bacteria (LAB) strains on color properties, phenolic profile and antioxidant activities of mulberry juice. Mulberry juice was separately fermented at 37 °C for 36 h using Lactobacillus plantarum, Lactobacillus acidophilus and Lactobacillus paracasei. The results showed that lactic acid fermentation impacted on the color of the juice. Moreover, the study demonstrated that LABs impacted on the phenolic profile of the juice. Syringic acid, cyanidin-3-O-rutinoside and quercetin were the predominant phenolic acid, anthocyanin and flavonol respectively in the lactic-acid-fermented mulberry juice. The degree of radical scavenging activity was species-specific with the L. plantarum fermented juice having the highest radical scavenging activities. The correlation analysis demonstrated that flavonols and anthocyanins were mostly responsible for the increased in 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) scavenging activity while phenolic acids and flavonols were responsible for 2,2-diphenyl-1-picrylhydrazyl scavenging activity and reducing power capacity of the fermented juice., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

This work investigates the potential bioconversion of spent coffee grounds (SCG) into lactic acid (LA). SCG were hydrolysed by a combination of dilute acid treatment and subsequent application of cellulase. The SCG hydrolysate contained a considerable amount of reducing sugars (9·02 ± 0·03 g l -1 , glucose; 26·49 ± 0·10 g l -1 galactose and 2·81 ± 0·07 g l -1 arabinose) and it was used as a substrate for culturing several lactic acid bacteria (LAB) and LA-producing Bacillus coagulans. Among the screened micro-organisms, Lactobacillus rhamnosus CCM 1825 was identified as the most promising producer of LA on a SCG hydrolysate. Despite the inhibitory effect exerted by furfural and phenolic compounds in the medium, reasonably high LA concentrations (25·69 ± 1·45 g l -1 ) and yields (98%) were gained. Therefore, it could be demonstrated that SCG is a promising raw material for the production of LA and could serve as a feedstock for the sustainable large-scale production of LA., Significance and Impact of the Study: Spent coffee grounds (SCG) represent solid waste generated in millions of tonnes by coffee-processing industries. Their disposal represents a serious environmental problem; however, SCG could be valorized within a biorefinery concept yielding various valuable products. Herein, we suggest that SCG can be used as a complex carbon source for the lactic acid production., (© 2018 The Society for Applied Microbiology.)

Lactic acid bacteria (LAB) can take advantage of fermentable carbohydrates to produce lactic acid. They are proverbially applied in industry, agricultural production, animal husbandry, food enterprise, pharmaceutical engineering and some other important fields, which are closely related to human life. For performing the probiotic functions, LAB have to face the low pH environment of the gastrointestinal tract. Therefore, acid resistance of LAB is of great importance not only for their own growth, but also for fermentation and preparation of probiotic products. Recent research studies on acid resistance mechanisms of LAB are mainly focused on neutralization process, biofilm and cell density, proton pump, protection of macromolecules, pre-adaptation and cross-protection, and effect of solutes. In this context, biotechnological strategies such as synthetic biology, genome shuffling, high pressure homogenization and adaptive laboratory evolution were also used to improve the acid resistance of LAB to respond to constantly changing low pH environment.

This research investigated the influence of lactic acid bacteria (LAB) strains on ester levels in Bordeaux red wines. These wines were made in five Bordeaux areas in two vintages, using three yeast strains. Malolactic fermentation (MLF) was carried out using industrial starters or indigenous strains, each in triplicate. Ester concentrations were determined by liquid-liquid-extraction- or HS-SPME-GC/MS at various stages in the winemaking process. The levels of most compounds were slightly impacted by LAB, depending on grape variety. Nevertheless, branched hydroxylated esters, such as ethyl 2-hydroxy-3-methylbutanoate and ethyl 2-hydroxy-4-methylpentanoate were the only compounds to be strongly influenced by the bacteria strain, regardless of matrix composition or the yeasts used for alcoholic fermentation. Moreover, the effect observed after MLF persisted over time, for at least 12months. These esters are apparently important markers of LAB esterase activity. To our knowledge, this was the first time they had been identified in this role., (Copyright © 2017 Elsevier Ltd. All rights reserved.)

Sucrose and inulin, when combined with glucose, behaved as stimulating agents of bacteriocin production by Pediococcus pentosaceus ATCC 43200. When such microbial strain was grown in glucose-based Man, Rogosa, and Sharpe (MRS) medium, without any additional supplement, it showed higher maximum cell concentration (2.68 ± 1.10 g/L) and longer generation time (2.17 ± 0.02 h), but lower specific growth rate (0.32 ± 0.01 h -1 ) than in the same medium supplemented with 1.0% of both ingredients (2.53 ± 1.10 g/L, 1.60 ± 0.05 h and 0.43 ± 0.02 h -1 , respectively). Glucose replacement by sucrose or inulin almost completely suppressed growth, hence confirming that it is the preferred carbon source for this strain. Qualitatively, similar results were observed for lactate production, which was 59.8% higher in glucose-based medium. Enterococcus and Listeria strains were sensitive to bacteriocin, whose antimicrobial effect after 8 h increased from 120.25 ± 0.35 to 144.00 ± 1.41 or 171.00 ± 1.41 AU/mL when sucrose or inulin was added to the glucose-based MRS medium. Sucrose and inulin were also able to speed up P. pentosaceus growth in the exponential phase.

Anti-Fusarium activities of lactic acid bacteria (LAB) Lactobacillus plantarum 299V, L. plantarum NRRL-4496, and Lactobacillus rhamnosus VT1 were determined by a microdilution assay developed in this study against Fusarium graminearum 08/RG/BF/51. A cell-free Lactobacillus culture supernatant (CFLCS) of L. rhamnosus VT1 had the highest anti-Fusarium activity. Response surface methodology was used to optimize the incubation conditions for production of CFLCS. A Box-Behnken factorial design was used to investigate the effects of incubation time, shaking speed, and incubation temperature on the inhibition rate of CFLCS. A model equation was generated to predict the inhibition rate of CFLCS under various incubation conditions. A low probability value (0.0012) and associated F value of 25.10 suggested that the model was highly significant. A high R 2 value (0.978) indicated a very satisfactory model performance. Response surface methodology analysis suggested that an incubation temperature at 34°C, a shaking speed at 170 rpm, and an incubation time of 55 h were the best combination for production of CFLCS from L. rhamnosus VT1. Under these incubation conditions, a 10% L. rhamnosus VT1 CFLCS solution was predicted to inhibit the growth of F. graminearum by 75.6% in vitro and inhibited 83.7% of the growth in the validation experiment. Thus, the CFLCS of L. rhamnosus VT1 was an effective anti-Fusarium mixture.

In order to improve the silage fermentation of stylo (Stylosanthes guianensis) in tropical areas, stylo silages were prepared with commercial additives Lactobacillus plantarum Chikuso-1 (CH1), L. rhamnasus Snow Lact L (SN), Acremonium cellulase (CE) and their combination as SN+CE or CH1 + CE, and the fermentation quality, chemical composition and ruminal degradation of these silages were studied. Stylo silages treated with lactic acid bacteria (LAB) or cellulase, the pH value and NH 3 -N ⁄ total-N were significantly (P < 0.05) decreased while the ruminal degradability of dry matter (DM), crude protein (CP), neutral detergent fiber (aNDFom) and acid detergent fiber (ADFom) were significantly (P < 0.05) increased compared to control. Compared to LAB or cellulase-treated silages, the DM, CP contents and relative feed value (RFV), and the ruminal degradability in LAB plus cellulase-treated silages were significantly (P < 0.05) higher, but the aNDFom content was significantly (P < 0.05) lower. CH1 + CE treatment was more effective in silage fermentation and ruminal degradation than SN+CE treatment. The results confirmed that LAB or LAB plus cellulase treatment could improve the fermentation quality, chemical composition and ruminal degradation of stylo silage. Moreover, the combined treatment with LAB and cellulase may have beneficial synergistic effects on ruminal degradation., (© 2017 Japanese Society of Animal Science.)

This study aims to define the aroma composition and key aroma compounds of barley malt wort beverages produced from fermentation using six lactic acid bacteria (LAB) strains. Gas chromatography mass spectrometry-olfactometry and flame ionization detection was employed; key aroma compounds were determined by means of aroma extract dilution analysis. Fifty-six detected volatile compounds were similar among beverages. However, significant differences were observed in the concentration of individual compounds. Key aroma compounds (flavor dilution (FD) factors ≥16) were β-damascenone, furaneol, phenylacetic acid, 2-phenylethanol, 4-vinylguaiacol, sotolon, methional, vanillin, acetic acid, nor-furaneol, guaiacol and ethyl 2-methylbutanoate. Furthermore, acetaldehyde had the greatest odor activity value of up to 4266. Sensory analyses revealed large differences in the flavor profile. Beverage from L. plantarum Lp. 758 showed the highest FD factors in key aroma compounds and was correlated to fruity flavors. Therefore, we suggest that suitable LAB strain selection may improve the flavor of malt based beverages., (Copyright © 2017 Elsevier Ltd. All rights reserved.)

The objective was to study effects of lactic acid bacteria (L) and molasses (M) on the microbial community and fermentation quality of soybean silage. Soybean was ensiled with no additive control (C), 0.5% molasses (0.5%M), 0.5%M+L (0.5%ML), 2%M, 2%M+L (2%ML) for 7, 14, 30 and 60days. The M-treated silages could increase the content of lactic acid and decrease butyric acid than control. Besides, higher crude protein was also observed in M-treated silages. With prolonged ensiling time, there was a reduction of the ratio of lactic acid/acetic acid in the 2%M-treated and 2%ML-treated silages. The combined addition of L and 2%M could enhance the account of desirable Lactobacillus and inhibit the growth of undesirable microorganism such as Clostridia and Enterobacter. In summary, the silage quality of soybean was improved with the addition of L and M., (Copyright © 2017 Elsevier Ltd. All rights reserved.)