Enhancement effect of l-cysteine on lactic acid fermentation production.

BACKGROUND: Environmental stress resistance is still a bottleneck for economical process for l-lactic acid fermentation. Chronological lifespan (CLS) extension has represented a promising strategy for improving stress resistance of microbial cell factories. MAIN METHODS AND MAJOR RESULTS: In this study, addition of anti-aging drug cysteine, a kind of extending CLS of microbial cell factories, was systematically evaluated on cell viability and l-lactic acid production in Bacillus coagulans CICC 23843. The results revealed that 16 mm l-cysteine supplement significantly improved l-lactic acid titer in B. coagulans. The enhanced total antioxidant capacity (T-AOC) and key enzymes activities involving in glycolytic pathway as well as differentially expressed genes involved in cysteine synthesize and cysteine precursor synthesize pathways, and fatty acid degradation pathway may help to further understand the relative mechanism of l-cysteine effect on improving l-lactic acid accumulation. Finally, based on 16 mm l-cysteine supplement, a final l-lactic acid titer of 130.5 g L-1 with l-lactic acid productivity of 4.07 g L-1  h-1 and the conversion rate of 0.94 g g-1 total sugar was achieved in a 5 L bioreactor. CONCLUSIONS AND IMPLICATIONS: This study provided a valuable option for engineering lactic acid bacteria lifespan for enhancement of lactic acid yield.

Does symbiotic supplementation which contains Bacillus Coagulans Lactobacillus rhamnosus, Lactobacillus acidophilus and fructooligosaccharide has favourite effects in patients with type-2 diabetes? A randomised, double-blind, placebo-controlled trial.

This study aimed to determine the effect of Bacillus Coagulans symbiotic supplementation on metabolic factors and inflammation in patients with type-2 diabetes. In this clinical trial, 50 patients with type-2 diabetes were randomly assigned to the symbiotic (containing Bacillus Coagulans + Lactobacillus rhamnosus + Lactobacillus acidophilus and fructooligosaccharide) or placebo groups to receive one sachet daily for 12 weeks. Glycaemic Index, lipid profile, and hs-CRP were measured at the beginning and end of the study. Analysis of covariance demonstrated that fasting blood glucose (FBG), insulin, homeostatic Model Assessment for Insulin Resistance (HOMA-IR), ß-cell function (HOMA-ß) (p <.05) and hs-CRP (p <.05) significantly declined in the treatment group compared with the placebo group. So, the current study indicated that Bacillus Coagulans symbiotic supplementation could improve metabolic factors and inflammation in patients with type-2 diabetes.

Theaflavin and its derivatives exert antibacterial action against Bacillus coagulans through adsorption to cell surface phospholipids.

AIMS: To investigate the antibacterial effects of tea theaflavins and catechins against Bacillus coagulans and the underlying mechanism of antibacterial action. METHODS AND RESULTS: Bactericidal activities of theaflavin and its analogues were evaluated and compared with that of epigallocatechin gallate. Theaflavin derivatives exhibited high bactericidal activity at 50 µmol L-1 , whereas epigallocatechin gallate did not, even at 500 µmol L-1 . Furthermore, we investigated the adsorption of theaflavins to model phospholipid membranes and corresponding effects on membrane fluidity to reveal their effects on the B. coagulans cell surface. Cell membrane fluidity was decreased after treatment with theaflavin derivatives with one or more galloyl moieties. Quartz-crystal microbalance analysis showed a strong affinity of the membrane phosphatidyl glycerol (PG) bilayers for theaflavin derivatives, correlating their bactericidal activity. CONCLUSION: These findings suggest that theaflavins could effectively inhibit B. coagulans by decreasing cell membrane fluidity. SIGNIFICANCE AND IMPACT: Bacillus coagulans is a spore-forming heat-resistant bacterium responsible for spoilage in low-acidic beverages. Natural antimicrobial components in tea-based beverages are central to reducing microbial contamination and product quality deterioration, although mechanisms underlying their antimicrobial action remain obscure. This study highlights the inhibitory action of theaflavins on B. coagulans and their potential application in food and beverage industries.

Difference in the antibacterial action of epigallocatechin gallate and theaflavin 3,3'-di-O-gallate on Bacillus coagulans.

AIMS: To study the mechanism of the antibacterial action of tea polyphenols such as catechins and theaflavins against Bacillus coagulans, and the interaction of epigallocatechin gallate (EGCg) or theaflavin 3,3'-di-O-gallate (TFDG) with the surface of B. coagulans cells was investigated. METHODS AND RESULTS: The antibacterial activities of EGCg and TFDG against B. coagulans cells were measured by counting of the viable cells after the mixing with each polyphenol. Bactericidal effect of TFDG was shown at the concentration of greater than or equal to 62·5 mg l-1 ; however, at the same concentration, EGCg did not. According to the results of two dimensional (2D)-electrophoresis analysis, TFDG seemed to interact with cytoplasmic membrane proteins. The activity of the glucose transporters of the cells decreased 40% following the treatment with TFDG of 62·5 mg l-1 ; however, this decrease was only slight in case of EGCg. This result was in accordance with the strength of their bactericidal activities. CONCLUSION: Our results suggest that the direct interaction between membrane proteins and TFDG is an important factor in the antibacterial activity of polymerized catechins, affecting their functions and leading to cell death. SIGNIFICANCE AND IMPACT OF THE STUDY: Tea polyphenols can effectively use the prevention of product spoilage in the food and beverage industry.

Biotechnological conversion of spent coffee grounds into lactic acid.

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.

Production of high concentration of l-lactic acid from oil palm empty fruit bunch by thermophilic Bacillus coagulans JI12.

Thermophilic Bacillus coagulans JI12 was used to ferment hemicellulose hydrolysate obtained by acid hydrolysis of oil palm empty fruit bunch at 50 °C and pH 6, producing 105.4 g/L of l-lactic acid with a productivity of 9.3 g/L/H by fed-batch fermentation under unsterilized conditions. Simultaneous saccharification and fermentation (SSF) was performed at pH 5.5 and 50 °C to convert both hemicellulose hydrolysate and cellulose-lignin complex in the presence of Cellic Ctec2 cellulases using yeast extract (20 g/L) as the nitrogen source, giving 114.0 g/L of l-lactic acid with a productivity of 5.7 g/L/H. The SSF was also conducted by replacing yeast extract with equal amount of dry Bakers' yeast, achieving 120.0 g/L of l-lactic acid with a productivity of 4.3 g/L/H. To the best of our knowledge, these lactic acid titers and productivities are the highest ever reported from lignocellulose hydrolysates.

Model-based characterisation of growth performance and l-lactic acid production with high optical purity by thermophilic Bacillus coagulans in a lignin-supplemented mixed substrate medium.

Three Bacillus coagulans strains were characterised in terms of their ability to grow in lignin-containing fermentation media and to consume the lignocellulose-related sugars glucose, xylose, and arabinose. An optical-density high-throughput screening was used for precharacterisation by means of different mathematical models for comparison (Logistic, Gompertz, Baranyi, Richards & Stannard, and Schnute). The growth response was characterised by the maximum growth rate and lag time. For a comparison of the screening and fermentation results, an unstructured mathematical model was proposed to characterise the lactate production, bacterial growth and substrate consumption. The growth model was then applied to fermentation procedures using wheat straw hydrolysates. The results indicated that the unstructured growth model can be used to evaluate lactate producing fermentation. Under the experimental fermentation conditions, one strain showed the ability to tolerate a high lignin concentration (2.5g/L) but lacked the capacity for sufficient pentose uptake. The lactate yield of the strains that were able to consume all sugar fractions of glucose, xylose and arabinose was ∼83.4%. A photometric measurement at 280nm revealed a dynamic change in alkali-lignin concentrations during lactate producing fermentation. A test of decolourisation of vanillin, ferulic acid, and alkali-lignin samples also showed the decolourisation performance of the B. coagulans strains under study.

The optimization of l-lactic acid production from sweet sorghum juice by mixed fermentation of Bacillus coagulans and Lactobacillus rhamnosus under unsterile conditions.

The cost reduction of raw material and sterilization could increase the economic feasibility of l-lactic acid fermentation, and the development of an cost-effective and efficient process is highly desired. To improve the efficiency of open fermentation by Lactobacillus rhamnosus based on sweet sorghum juice (SSJ) and to overcome sucrose utilization deficiency of Bacillus coagulans, a mixed fermentation was developed. Besides, the optimization of pH, sugar concentration and fermentation medium were also studied. Under the condition of mixed fermentation and controlled pH, a higher yield of 96.3% was achieved, compared to that (68.8%) in sole Lactobacillus rhamnosus fermentation. With an optimized sugar concentration and a stepwise-controlled pH, the l-lactic acid titer, yield and productivity reached 121gL(-1), 94.6% and 2.18gL(-1)h(-1), respectively. Furthermore, corn steep powder (CSP) as a cheap source of nitrogen and salts was proved to be an efficient supplement to SSJ in this process.

Fermentative lactic acid production from coffee pulp hydrolysate using Bacillus coagulans at laboratory and pilot scales.

In this study, the lignocellulosic residue coffee pulp was used as carbon source in fermentative l(+)-lactic acid production using Bacillus coagulans. After thermo-chemical treatment at 121°C for 30min in presence of 0.18molL(-1) H2SO4 and following an enzymatic digestion using Accellerase 1500 carbon-rich hydrolysates were obtained. Two different coffee pulp materials with comparable biomass composition were used, but sugar concentrations in hydrolysates showed variations. The primary sugars were (gL(-1)) glucose (20-30), xylose (15-25), sucrose (5-11) and arabinose (0.7-10). Fermentations were carried out at laboratory (2L) and pilot (50L) scales in presence of 10gL(-1) yeast extract. At pilot scale carbon utilization and lactic acid yield per gram of sugar consumed were 94.65% and 0.78gg(-1), respectively. The productivity was 4.02gL(-1)h(-1). Downstream processing resulted in a pure formulation containing 937gL(-1)l(+)-lactic acid with an optical purity of 99.7%.

Leguminose green juice as an efficient nutrient for l(+)-lactic acid production.

Lactic acid is one of the most important building blocks for the production of bioplastic. Many investigations have been conducted to reduce the lactic acid production costs. In this work, the focus was put on the application of legume pressed juice or green juice as nutrient source. The pressed juice was utilized directly without prior pre-treatment and sterilization. Using two different alfalfa green juices and a clover green juice from two different harvest years as sole nutrients, non-sterile fermentations were performed at 52°C and pH 6.0 with a thermotolerant strain Bacillus coagulans AT107. The results showed that alfalfa green juices generally were more suitable for high lactic acid production than clover green juices, presumably due to the higher nitrogen content. A final titer of 98.8g/L after 30h with l(+)-lactic acid purity of >99% was obtained.

Fermentative utilization of coffee mucilage using Bacillus coagulans and investigation of down-stream processing of fermentation broth for optically pure l(+)-lactic acid production.

In this study, mucilage, a residue from coffee production, was investigated as substrate in fermentative l(+)-lactic acid production. Mucilage was provided as liquid suspension consisting glucose, galactose, fructose, xylose and sucrose as free sugars (up to 60gL(-1)), and used directly as medium in Bacillus coagulans batch fermentations carried out at 2 and 50L scales. Using mucilage and 5gL(-1) yeast extract as additional nitrogen source, more than 40gL(-1) lactic acid was obtained. Productivity and yield were 4-5gL(-1)h(-1) and 0.70-0.77g lactic acid per g of free sugars, respectively, irrespective the scale. Similar yield was found when no yeast extract was supplied, the productivity, however, was 1.5gL(-1)h(-1). Down-stream processing of culture broth, including filtration, electrodialysis, ion exchange chromatography and distillation, resulted in a pure lactic acid formulation containing 930gL(-1)l(+)-lactic acid. Optical purity was 99.8%.

Effects of beta-carotene fortified synbiotic food on metabolic control of patients with type 2 diabetes mellitus: A double-blind randomized cross-over controlled clinical trial.

BACKGROUND & AIMS: The aim of the present study was to determine the beneficial effects of beta-carotene fortified synbiotic food intake on metabolic status in patients with type 2 diabetes mellitus (T2DM). METHODS: This randomized double-blinded placebo-controlled crossover clinical trial was conducted among 51 patients with T2DM. Individuals were randomly assigned to take either a beta-carotene fortified synbiotic (n = 51) or control food (n = 51) for 6 weeks. The beta-carotene fortified synbiotic was containing Lactobacillus sporogenes (1 × 10(7) CFU), 0.1 g inulin and 0.05 g beta-carotene. Control food (the same substance without probiotic, inulin and beta-carotene) was packed in identical 9-g packages. Patients were requested to use the beta-carotene fortified synbiotic and control foods three times a day. RESULTS: Beta-carotene fortified synbiotic food consumption resulted in a significant decrease in insulin (-1.00 ± 7.90 vs. +3.68 ± 6.91 µIU/mL, P = 0.002), HOMA-IR (-0.73 ± 3.96 vs. +1.82 ± vbnm4.09, P = 0.002), HOMA-B (-0.52 ± 19.75 vs. +8.71 ± 17.15, P = 0.01), triglycerides (-2.86 ± 49.53 vs. +20.14 ± 50.10 mg/dL, P = 0.02), VLDL-cholesterol levels (-0.57 ± 9.90 vs. +4.03 ± 10.02 mg/dL, P = 0.02) and total-/HDL-cholesterol ratio (-0.01 ± 1.08 vs. +0.64 ± 0.81, P = 0.001) compared to the control food. In addition, beta-carotene fortified synbiotic food consumption led to elevated plasma nitric oxide (NO) (+6.83 ± 16.14 vs. -3.76 ± 16.47 µmol/L, P = 0.001) and glutathione (GSH) (+36.58 ± 296.71 vs. -92.04 ± 243.05 µmol/L, P = 0.01). CONCLUSIONS: Beta-carotene fortified synbiotic food intake in patients with T2DM for 6 weeks had favorable effects on insulin, HOMA-IR, HOMA-B, triglycerides, VLDL-cholesterol, total-/HDL-cholesterol ratio, NO and GSH levels.