Direct Lactic Acid Production Research Articles

Direct lactic acid production from raw jerusalem artichoke powder by Lacticaseibacillus paracasei NJ and the comparative transcriptomic profiling of inulin and monosaccharide utilization

A feasible fermentation process for the production of lactic acid (LA), one of the most important food additives, from non-crop feedstocks would help alleviate the challenges of food safety. In this study, 215 g/L inulin-rich Jerusalem artichoke powder (JAP) were directly converted into LA without exogenous nitrogen addition under non-sterile conditions via selected Lacticaseibacillus paracasei NJ. The LA concentration, yield, and average productivity reached 144.08 g/L, 0.67 g/g, and 4.37 g/L/h, respectively, which can be scalable from 5 L to 50 L bioreactors. The viable counts of Lacticaseibacillus reached to 142.30–301.50 × 108 CFU/mL, allowing the products a promising probiotic in food additives. Transcriptional analysis revealed that strain NJ utilized inulin mainly via extracellular β-fructosidase and fructose transporters encoded by the fosRABCDXE operon, and the gene expression within the phosphoenolpyruvate (PEP)-dependent phosphotransferase system (PTS), pyruvate metabolism, and fatty acid synthesis was significantly altered. For strain NJ grown on JAP, the expressions of genes related to amino acid biosynthesis and peptide/amino acid relevant ATP-binding cassette (ABC) transport system were upregulated to fit nitrogen limitation. We found the availability of L. paracasei NJ for high-yield lactic acid from raw JAP and explores the inner changes of gene expression by utilizing inulin, which provide both promising food additives and new perspectives on the understanding of inulin metabolism in Lacticaseibacillus.

Direct lactic acid production from household food waste by lactic acid bacteria

China is vigorously promoting garbage classification, but the treatment of classified waste, especially household food waste (HFW) has yet to be studied. Lactic acid (LA), a high value-added platform molecule has broad market prospects. Although there have been many studies on the production of LA from food waste, open fermentation often produces lots of by-products, while the traditional fermentation under a pure bacteria system often requires the saccharification process, which increases the production cost. We sought to analyze the comprehensive properties of classified HFW in Shanghai, then to produce LA by inoculating lactic acid bacteria (LAB) directly. The effects of strains, temperature, sterilized or not, initial pH, inoculum size, and substrate concentration on LA production were investigated. HFW was rich in nutrients and growth factors which provided the possibility for direct LA production from HFW by inoculating LAB. The results showed that Lactobacillus rhamnosus ATCC 7469, Lactobacillus delbrueckii subsp. bulgaricus and Streptococcus thermophilus all could be used as the inoculum, however, no significant synergistic effect of the three strains on LA production was found. LA concentration of 30.25 g/L at 37 °C, pH 6.8 could be obtained by inoculating Lactobacillus rhamnosus ATCC 7469 from sterilized HFW. High inoculum size and substrate concentration resulted in high LA concentration, but not high LA yield. The result of ANOVA indicated that there was a significantly positive relationship between substrate concentration and LA concentration (r = 0.942, p < 0.01), while no statistically significant difference between these groups at different inoculum size was evident (p = 0.318). In addition, an average LA concentration of 26.8 g/L, LA yield of 0.20 g/g TCOD was obtained by repeated batch fermentation for 32 d.

Direct Lactic Acid Production from Household Food Waste by Lactic Acid Bacteria

Direct Lactic Acid Production from Household Food Waste by Lactic Acid Bacteria

Direct Lactic Acid Production from Household Food Waste by Lactic Acid Bacteria

Direct Lactic Acid Production from Household Food Waste by Lactic Acid Bacteria

Free-nutrient supply and thermo-alkaline conditions for direct lactic acid production from mixed lignocellulosic and food waste materials

This study aimed to achieve effective lactic acid (LA) production from waste materials. From natural sources on banana peels-containing media, 253 bacterial isolates were obtained. Isolate FW26 was selected for LA production from untreated banana peels (no pre-treatment) at pH 9.0 and 50 °C. It was identified as Enterococcus faecium strain FW26 using 16S rRNA sequencing. The optimal solid-to-liquid ratio was 1:10 (w/v) achieving LA at 15.9 g L−1 from direct utilization of banana peels. Utilization of co-substrates achieved positive synergistic effects on growth and LA production. Fermentation of banana peels and food wastes mixture (1:1.5, w/w) exhibited 22.2% improvements in LA concentration. Besides, exclusion of medium components achieved comparable LA fermentation parameters to that obtained with nutrient supplementation. Moreover, controlling of fermentation pH exhibited 81% improvements in LA concentration achieving 33.3 ± 2.6 g L−1 with yield of 0.84 g g−1-consumed sugars. This indicate the potentiality of strain FW26 for LA production by direct utilization of untreated mixed wastes without nutrient supplementation under thermo-alkaline conditions.

Consolidated bioprocessing of lignocellulosic biomass to lactic acid by a synthetic fungal-bacterial consortium.

Consolidated bioprocessing (CBP) of lignocellulosic feedstocks to platform chemicals requires complex metabolic processes, which are commonly executed by single genetically engineered microorganisms. Alternatively, synthetic consortia can be employed to compartmentalize the required metabolic functions among different specialized microorganisms as demonstrated in this work for the direct production of lactic acid from lignocellulosic biomass. We composed an artificial cross-kingdom consortium and co-cultivated the aerobic fungus Trichoderma reesei for the secretion of cellulolytic enzymes with facultative anaerobic lactic acid bacteria. We engineered ecological niches to enable the formation of a spatially structured biofilm. Up to 34.7 gL-1 lactic acid could be produced from 5% (w/w) microcrystalline cellulose. Challenges in converting pretreated lignocellulosic biomass include the presence of inhibitors, the formation of acetic acid and carbon catabolite repression. In the CBP consortium hexoses and pentoses were simultaneously consumed and metabolic cross-feeding enabled the in situ degradation of acetic acid. As a result, superior product purities were achieved and 19.8 gL-1 (85.2% of the theoretical maximum) of lactic acid could be produced from non-detoxified steam-pretreated beech wood. These results demonstrate the potential of consortium-based CBP technologies for the production of high value chemicals from pretreated lignocellulosic biomass in a single step.

Mechanocatalytic Production of Lactic Acid from Glucose by Ball Milling

A solvent-free process was developed for the direct production of lactic acid from glucose in a mechanocatalytic process in the presence of Ba(OH)2, and a moderate lactic acid yield of 35.6% was obtained. Glucose conversion and lactic acid formation were favorable at higher catalyst/glucose mass ratios. However, at relatively lower catalyst/glucose mass ratios, they were greatly inhibited, and the promotion of fructose formation was observed. The mechanocatalytic process was applicable for various carbohydrates such as C5 sugars, C6 sugars, and disaccharides with 20–36% lactic acid yields achieved. This work provides a new pathway for the production of value-added chemicals from biomass resources.

Amylolytic Enzymes Acquired from L-Lactic Acid Producing Enterococcus faecium K-1 and Improvement of Direct Lactic Acid Production from Cassava Starch.

An amylolytic lactic acid bacterium isolate K-1 was isolated from the wastewater of a cassava starch manufacturing factory and identified as Entercoccus faecium based on 16S rRNA gene sequence analysis. An extracellular α-amylase was purified to homogeneity and the molecular weight of the purified enzyme was approximately 112kDa with optimal pH value and temperature measured of 7.0 and 40°C, respectively. It was stable at a pH range of 6.0-7.0, but was markedly sensitive to high temperatures and low pH conditions, even at a pH value of 5. Ba2+, Al3+, and Co2+ activated enzyme activity. This bacterium was capable of producing 99.2% high optically pure L-lactic acid of 4.3 and 8.2g/L under uncontrolled and controlled pH at 6.5 conditions, respectively, in the MRS broth containing 10g/L cassava starch as the sole carbon source when cultivated at 37°C for 48h. A control pH condition of 6.5 improved and stabilized the yield of L-lactic acid production directly from starch even at a high concentration of starch at up to 150g/L. This paper is the first report describing the properties of purified α-amylase from E. faecium. Additionally, pullulanase and cyclodextrinase activities were also firstly recorded from E. faecium K-1.

Screening for Direct Production of Lactic Acid from Rice Starch Waste by Geobacillus stearothermophilus

Lactic acid recently became an important chemical where it is widely used in many industries such as food, cosmetic, chemical and pharmaceutical industry. The present study focuses on the screening for lactic acid production from rice starch waste using a thermophilic amylolytic bacterium, Geobacillus stearothermophilus . There is no information available on direct fermentation of lactic acid from rice starch waste using G. stearothermophilus . The effects of different parameters such as temperature, pH, incubation time, agitation speed, concentration of nitrogen and carbon sources on the lactic acid production were assessed. The highest concentration of lactic acid produced was 5.65 ± 0.07 g/L at operating conditions of 60°C, pH 5.5, 48 h, 200 rpm of agitation speed with 5% concentrations of both carbon and nitrogen source. The findings indicated that rice starch waste can be successfully converted to lactic acid by G. stearothermophilus .

Direct production of lactic acid based on simultaneous saccharification and fermentation of mixed restaurant food waste

This study introduces to a one-step process for the fermentative production of L(+)-lactic acid from mixed restaurant food waste. Food waste was used as carbon and nitrogen source in simultaneous saccharification and fermentation (SSF) using Lactobacillus sp. or Streptococcus sp. strains for L(+)-lactic acid production. Waste consisted of (w/w) 33.5% starch, 14.8% proteins, 12.9% fat and 8.5% free sugars. Lactobacillus sp. strains showed a productivity of 0.27–0.53 g L−1 h−1 and a yield of 0.07–0.14 g g−1 of theoretically available sugars, while Streptococcus sp. more efficiently degraded the food waste material and produced lactic acid at a maximum rate of 2.16 g L−1 h−1 and a yield of 0.81 g g−1. For SSF, no enzymes were added or other hydrolytic treatments were carried out. Outcomes revealed a linear relationship between lactic acid concentration and solid-to-liquid ratio when Streptococcus sp. was applied. Statistically, from a 20% (w/w) dry food waste blend 52.4 g L−1 lactic acid can be produced. Experimentally, 58 g L−1 was achieved in presence of 20% (w/w), which was the highest solid-to-liquid ratio that could be treated using the equipment applied. Irrespective if SSF was performed at laboratory or technical scale, or under non-sterile conditions, Streptococcus sp. efficiently liquefied food waste and converted the released nutrients directly into lactic acid without considerable production of other organic acids, such as acetic acid. Downstream processing including micro- and nanofiltration, electrodialysis, chromatography and distillation gave a pure 702 g L−1 L(+)-lactic acid formulation.

Direct lactic acid production from beech wood by transgenic white-rot fungus Phanerochaete sordida YK-624

A lactic acid (LA)-producing strain of the hyper-lignin-degrading fungus Phanerochaete sordida YK-624 with the lactate dehydrogenase-encoding gene from Bifidobacterium longum (Blldh) was constructed. When the endogenous pyruvate decarboxylase gene-knocked down and Blldh-expressing transformant was cultured with beech wood meal, the transformant was able to successively delignify and ferment the substrate. Supplementation of calcium carbonate into the culture medium, significantly increased the level of LA accumulation. Direct LA production (at 0.29g/l) from wood was confirmed, and additional inclusion of exogenous cellulase in this fermentation yielded significant further improvement in LA accumulation (up to 1.44g/l). This study provides the first report of direct production of LA by fermentation from woody biomass by a single microorganism, and indicates that transgenic white-rot fungi have a potential use for development of simple/easy applications for wood biorefinery.

Efficient secretory expression of gene encoding a broad pH-stable maltose-forming amylase from Lactobacillus plantarum S21 in food-grade lactobacilli host

The native and the N-terminal signal peptide sequence deleted gene encoding for α-amylase from Lactobacillus plantarum S21 were cloned into the inducible lactobacilli expression vectors pSIP409 and pSIP609 and expressed in L. plantarum WCFS1 and food-grade L. plantarum TGL02, respectively. Only the native amylase gene was expressed and secreted extracellular amylase at a level of approximately 2000 U/L with 90 % secretion efficiency from both hosts. The purified extracellular amylase from the L. plantarum TGL02 retained unique properties of the wild-type enzyme, particularly the broad pH stability (4.0–8.0) and maltose-forming activity. The results indicate high compatibility of L. plantarum S21 signal peptide sequence to both recombinant lactobacilli hosts. The recombinant lactobacilli exhibited high efficiency for direct lactic acid production from starch as found with L. plantarum S21. The efficient compatible signal peptide is also expected to be applied in secretory expression for production of valuable proteins in food-grade lactobacilli host.

Starchy effluent from rice noodle manufacturing process as feasible substrate for direct lactic acid production by Lactobacillus plantarum S21

In utilization of both starch containing wastewater and gelatinized starchy waste, Lactobacillus plantarum S21 demonstrated the high capability of lactic acid production directly from starchy effluent and maintained its potency even at high concentration of initial starchy substrate of 40, 60 and 80 g/L by maximum yielding 1.00±0.06, 0.89±0.03, 0.90±0.07 g/g substrate, productivity of 0.79±0.06, 0.98±0.00, 1.23±0.07 g/L·h and production efficiency of 94.6, 78.8, and 74.3%, respectively, at 48 h fermentation. This is the first report on direct conversion of starchy wastes to lactic acid by amylolytic lactic acid bacterium using high concentration of starchy substrate.

Modelling and simulation of continuous L (+) lactic acid production from sugarcane juice in membrane integrated hybrid-reactor system

Modelling and simulation was done for a two-stage membrane-integrated hybrid reactor system for continuous production of L (+) lactic acid under non-neutralizing conditions. The model captures microbial conversion of sugar cane juice to lactic acid under substrate–product inhibitions with downstream purification by nanofiltration. All the major phenomena and the governing parameters like fluid flow, feed dilution, substrate–product inhibitions, Donnan and steric effects during micro and nanofiltration for cell recycle, product separation and purification have been reflected in the modelling. The model describes a green, integrated continuous process of direct lactic acid production starting with a cheap, renewable carbon source. The highest lactic acid concentration achieved after the final stage of nanofiltration was 66.97g/L at 13kg/cm2 operating pressure when the overall productivity reached 12.40g/(Lh). The developed model could successfully predict production, purification and transport of lactic acid through two stage membrane modules. Performance of the model was very good as indicated in the high overall correlation coefficient (R2>0.980) and the low relative error (RE<0.1).

Starch‐modifying enzymes of lactic acid bacteria – structures, properties, and applications

AbstractIn spite that lactic acid bacteria (LAB) are used for production of fermented foods and drinks for millennia, their ability to grow using starch as a sole carbon source was noticed by the scientists in the last 30 years. A number of amylolytic LAB (ALAB) strains were isolated and several detailed investigations of biochemical and genetic basis of starch hydrolysis were performed. The purpose of this review is to summarize for the first time the available data about the starch‐modifying enzymes in ALAB. The most important amylolytic representatives of the genera Lactobacillus, Lactococcus, Streptococcus, Pediococcus, Carnobacterium, and Weissella are described. Amino acid sequences, corresponding to ALAB amylase enzymes are compared and some features of the gene expression are analyzed. The possible application of ALAB strains for direct production of lactic acid from starch, as well as their participation in food manufacturing is discussed.

5503717 Method of manufacturing flexible graphite

A lactic acid (LA)-producing strain of the hyper-lignin-degrading fungus Phanerochaete sordida YK-624 with the lactate dehydrogenase-encoding gene from Bifidobacterium longum (Blldh) was constructed. When the endogenous pyruvate decarboxylase gene-knocked down and Blldh-expressing transformant was cultured with beech wood meal, the transformant was able to successively delignify and ferment the substrate. Supplementation of calcium carbonate into the culture medium, significantly increased the level of LA accumulation. Direct LA production (at 0.29 g/l) from wood was confirmed, and additional inclusion of exogenous cellulase in this fermentation yielded significant further improvement in LA accumulation (up to 1.44 g/l). This study provides the first report of direct production of LA by fermentation from woody biomass by a single microorganism, and indicates that transgenic white-rot fungi have a potential use for development of simple/easy applications for wood biorefinery.

Direct fermentation of starch to lactic acid byLactobacillus amylovorus

Fermentation production of lactic acid directly from starch was studied in a batch fermentor usingLactobacillus amylovorus. At an initial concentration of 120 g/L starch, 96.2 g/L of lactic acid was produced from liquefied starch in 20 hours while 92.5 g/L of lactate was produced from the raw starch in 39 hours. High initial glucose levels (100 g/L) in the medium inhibited the organism, unless it had been adapted by growing it in a low-glucose medium. The direct production of lactic acid from starch could reduce overall production costs significantly.