Amylolytic Lactic Acid Bacteria Research Articles

Pemanfaatan Bakteri Asam Laktat (BAL) Amilolitik untuk Fermentasi Tepung Terigu dan Gandum

The national demand for carbohydrates in flour continues to increase significantly due to the emergence of contemporary food products that use flour as the primary ingredient. One of the products used in producing food is sourdough, which is fermented flour. Lactic acid bacteria (LAB) have a role in food fermentation by producing lactic acid. Amylolytic LAB can produce amylase enzyme, a biocatalyst in the starch hydrolysis process. One of the products made from the fermentation of wheat flour is sourdough. This study aims to determine the character of amylolytic LAB in wheat and wheat flour fermentation. The research methods include rejuvenation of LAB, selection of isolates, fermentation of starchy materials, and characterization of fermented liquid. The selection of bacteria was based on cell viability and pH, which showed that isolated Pediococcus pentasaceus E1222 could be used as a starter for starchy fermentation. The highest total acid and cell viability were produced in 24-hour wheat and wheat flour fermentation. Fermented wheat flour and flour had the most favorable aroma and texture, and fermented flour had the most favorable taste. Isolate Pediococcus pentasaceus E1222 is an isolate that can be used in making sourdough.

Isolation of Amylolytic Lactic Acid Bacteria from Cow, Goat and Sheep Milk in Yola Town, Adamawa State, Nigeria

In this study, lactic acid bacteria (LAB) were isolated from fresh milk samples from cow, sheep, and goat using MRS agar as a growth medium. Lactobacillusplantarum, Lactobacillusacidophilus, Lactobacillusfermentum, Enterococcusgallinarum, and Enterococcusfaecium were the species of LAB that were isolated and identified using the Vitek 2 compact system. While Lactobacillus fermentum, Enterococcus faecium, and Lactobacillus plantarum were isolated from goat milk, Lactobacillus acidophilus, Lactobacillus gallinarum, and Lactobacillus plantarum were isolated from cow milk.However, from sheep milk, only Lactobacillus plantarum and Lactobacillus acidophilus were isolated. All the isolates were subjected to amylase production test using modified MRS media and the results showed that Lactobacillus plantarum, Lactobacillusacidophilus and Lactobacillusfermentum produced amylase while Enterococcus gallinarum and Enterococcus faecium did not produce amylase.

Amylolytic lactic acid bacteria as starter cultures for malt quality improvement

Amylolytic lactic acid bacteria as starter cultures for malt quality improvement

Ethanol Production by Co-Cultivation of Yeast and Lactic Acid Bacteria on Starch

The co-cultivation of GRAS amylolytic bacteria together with ethanol-producing yeast Saccharomyces cerevisiae in starch-containing media might be one of the ways solving the problem of starch-containing waste disposal with simultaneous formation of ethanol as a potential biofuel for increasing octane number of gasoline. The aim of the study was to test the combination of microorganisms (amylolytic lactic acid bacteria and yeast) suitable for co-cultivation on starch and to optimize the conditions for starch cofermentation. Methods. Conventional microbiological, biochemical and statistical methods, including serial dilution technique with counting colony forming units (CFU) for growth assessment of mixed cultures, Gas Chromatograph/Mass Spectrometer (GC/MS) for measuring ethanol concentration and Box-Behnken experimental design (Statistica 10) for bioethanol production optimization, were used in this work. Results. The combination of microorganisms for mixed cultures co-cultivation in single-stage starch fermentation was established: the strain of ethanol-producing yeast S. cerevisiae UCM Y-527 and the amylolytic strain of lactic acid bacteria Streptococcus bovis IMV B-7151. Mathematical simulation using a Box-Behnken (3k-p) design determined the optimal parameters for the fermentation of starch in the process of co-cultivation of yeast and bacteria: 10 g/L of starch in the medium at simultaneous inoculations of both cultures and co-cultivation for 72 hours. The theoretically obtained parameters data were experimentally verified: the maximum ethanol yield 1.95 g/L in the experiment corresponded to the theoretically calculated values. Conclusions. It was suggested and optimized a method of starch cofermentation using strains of amylolytic lactic acid bacteria S. bovis IMV B-7151 and yeast S. cerevisiae UCM Y-527, which can be used for one-stage process of hydrolysis and fermentation of starch and starchcontaining wastes with the production of bioethanol and microbial biomass.

Efficient Secretion and Recombinant Production of a Lactobacillal α-amylase in Lactiplantibacillus plantarum WCFS1: Analysis and Comparison of the Secretion Using Different Signal Peptides.

Lactic acid bacteria (LAB) have been used as starter cultures and producers of enzymes, antimicrobial peptides or metabolites that contribute to the flavor, texture and safety of food products. Lactiplantibacillus plantarum, one of the best-studied LAB, is considered as safe and effective cell factory for food applications. In this study, our aim was to use L. plantarum as the producer for high levels of a food-grade lactobacillal α-amylase, which has potential applications in food, fermentation and feed industries. The native form of an α-amylase (AmyL) from L. plantarum S21, an amylolytic LAB isolated from Thai fermented rice noodles, was expressed in L. plantarum WCFS1 using the pSIP expression system. The secretion of the α-amylase was driven by the native signal peptides of the α-amylases from L. plantarum S21 (SP_AmyL) and Lactobacillus amylovorus NRRL B-4549 (SP_AmyA), as well as by three Sec-type signal peptides derived from L. plantarum WCFS1; Lp_2145, Lp_3050, and Lp_0373. Among the tested signal peptides, Lp_2145 appears to be the best signal peptide giving the highest total and extracellular enzymatic activities of α-amylase AmyL from L. plantarum S21, which were 13.1 and 8.1 kU/L of fermentation, respectively. These yields were significantly higher than the expression and secretion in L. plantarum WCFS1 using the native signal peptide SP_AmyL, resulting in 6.2- and 5.4-fold increase in total and extracellular activities of AmyL, respectively. In terms of secretion efficiency, Lp_0373 was observed as the most efficient signal peptide among non-cognate signal peptides for the secretion of AmyL. Real-time reverse-transcriptase quantitative PCR (RT-qPCR) was used to estimate the mRNA levels of α-amylase transcript in each recombinant strain. Relative quantification by RT-qPCR indicated that the strain with the Lp_2145 signal peptide-containing construct had the highest mRNA levels and that the exchange of the signal peptide led to a change in the transcript level of the target gene.

Fermentation of amylolytic yeast and lactic acid bacteria to improve the quality of modified cassava

The amylolytic activity has been studied in yeast and lactic acid bacteria (LAB) which are isolated from various types of traditional fermented cassava. The study aimed to obtain yeast and LAB isolates which high amylolytic activity for inoculum in cassava fermentation. A total of 23 yeasts and 22 LAB isolates were isolated from Gatot, Tiwul, Tapai, and Cassava fermented using chloramphenicol yeast glucose (CYG) media for yeast and de Man Rogosa Sharpe agar (MRSA) + CaCO3 for LAB. Yeast amylolytic activity was tested using yeast extract peptone starch agar medium, while the amylolytic LAB used MRS + starch media with Lugol’s iodine indicator. Colonies showing clear zone areas were measured as amylase activity on the iodine complex method. Isolates that have the highest amylolytic activity were used as inoculum in cassava fermentation. Yeast Tr7 and LAB G6 isolates showed the highest amylolytic activity (0.0624 U/mL and 0.0627 U/mL). Cassava fermentation products using yeast Tr7 and BAL G6 resulted 52.06% of hydrogen cyanide (HCN) reduction higher than without inoculum (32.32%). According to biochemical identification using API 50 CHL kit, LAB G6 isolate was 99.6% identical with Pediococcys pentosaceus whereas biochemical identification using API 20 C AUX showed that yeast Tr7 was 95.8% identical with Candida tropicalis. The biochemical identification result was similar to the molecular identification result. In molecular identification using 28S rRNA sequence analysis revealed that yeast Tr7 was 99% similar with Candida tropicalis NITCSK13 strain. LAB G6 was 100% similar with Pediococcus pentosaceus BSS1375 strain using 16S rRNA sequence analysis. C. tropicalis Tr7 and P. pentosaceus G6 potentially used for inoculum in cassava fermentation process to improve cassava quality as a functional food.

Utilizing Gelatinized Starchy Waste from Rice Noodle Factory as Substrate for L(+)-Lactic Acid Production by Amylolytic Lactic Acid Bacterium Enterococcus faecium K-1.

To valorize starchy waste from rice noodle factory, bioconversion of gelatinized starchy waste (GSW) to value-added product as L(+)-lactic acid, the monomer for polylactate synthesis, was investigated using amylolytic lactic acid bacterium, Enterococcus faecium K-1. Screening for appropriate nitrogen source to replace expensive organic nitrogen sources revealed that corn steep liquor (CSL) was the most suitable regarding high efficacy for L(+)-LA achievement and low-cost property. The successful applying statistic experimental design, Plackett-Burman design incorporated with central composite design (CCD), predicted the maximum L(+)-LA of 93.07g/L from the optimized medium (OM) containing 125.7g/L GSW and 207.3g/L CSL supplemented with CH3COONa, MgSO4, MnSO4, K2HPO4, CaCl2, (NH4)2HC6H5O7, and Tween80. Minimizing the medium cost by removal of all inorganic salts and Tween80 from OM was not an effect on L(+)-LA yield. Fermentation using the optimized medium without minerals (OM-Mi) containing only GSW (125.7g/L) and CSL (207.3g/L) in a 10-L fermenter was also successful. Thinning GSW with α-amylase from Lactobacillus plantarum S21 increased L(+)-LA productivity in the early stage of 24-h fermentation. Not only showing the feasible bioconversion process for GSW utilizing as a substrate for L(+)-LA production, this research also demonstrated the efficient model for industrial starchy waste valorization.

Probiotic potential and amylolytic properties of lactic acid bacteria isolated from Chinese fermented cereal foods

This study investigated the probiotic potential and amylase properties of amylolytic lactic acid bacteria (ALAB) isolated from fermented cereal-based foods in China. Of 132 LAB isolates screened for amylase production, three (430, 445, and 472) were found to have high amylase activities (8.15, 9.23, and 8.06 U/mL in MRS-1% starch broth, respectively). These three strains were identified as Lactobacillus plantarum by 16 S rRNA sequencing. Optimization of the starch content in the culture broth, pH, and temperature during fermentation revealed that the highest amylase activity (15.89 ± 0.51 U/mL) was found in L. plantarum 445. Moreover, the three ALAB isolates were assessed for their probiotic properties, tolerance to low pH, bile salt resistance, and antimicrobial and aggregation activities. All three ALAB isolates showed good survival at pH 2.0 and 3.0 and were resistant to 0.3% and 0.6% bile salts after 48 h of incubation. They also had different antimicrobial activities against five food-borne pathogens and similar intrinsic and non-transmissible antibiotic susceptibilities. The isolates had higher auto-aggregation ability but weaker co-aggregation ability than the reference strain, Lactobacillus rhamnosus ATCC 53103. These data demonstrate that the three ALAB isolates possess potential probiotic characteristics, suggesting that they are suitable candidates for cereal-based probiotic products and starter cultures for improving the cereal fermentation process.

Simultaneous Bioconversion of Gelatinized Starchy Waste from the Rice Noodle Manufacturing Process to Lactic Acid and Maltose-Forming α-Amylase by Lactobacillus plantarum S21, Using a Low-Cost Medium

A direct bioconversion of gelatinized starchy waste (GSW) to lactic acid by amylolytic lactic acid bacterium Lactobacillus plantarum S21 was investigated. Corn steep liquor (CSL) was selected as the most suitable low-cost nitrogen source for replacing yeast extract, beef extract, and peptone in De Man, Rogosa and Sharpe (MRS) medium. Plackett–Burman design results indicated that GSW and CSL were the two most nutrients that significantly influence lactic acid production, among eight medium components, including GSW, CSL, K2HPO4, CH3COONa, (NH4)2HC6H5O7, MgSO4, MnSO4, and Tween 80. A new low-cost medium containing only GSW (134.4 g/L) and CSL (187.7 g/L) was achieved as omitting other six components from the optimized medium had no effect on lactic acid yield. Batch fermentation at 37 °C both in 1 L and 10 L jar fermenters showed non-significantly different productivity. A by-product, maltose-forming α-amylase, was successfully achieved up to 96% recovery yield using an ultrafiltration unit equipped with a 50 kDa cut-off membrane. Crude lactic acid exhibited the additional benefit of antimicrobial activity against food and feed pathogens Salmonella enterica serovar Typhimurium TISTR 292, Vibrio cholerae TH-001, and also E. coli ATCC 25922. This study presents a promising bioprocess for the simultaneous production of lactic acid, and a value-added food enzyme, using only two industrial wastes, GSW and CSL, as the medium components.

Lactic Acid Fermentation of Arabinoxylan From Nejayote by Streptococcus infantarius ssp. infantarius 25124 Isolated From Pozol.

Streptococcus infantarius ssp. infantarius 25124 (Sii-25124) is a lactic acid bacterium (LAB) isolated from pozol, a refreshing beverage prepared by suspending fermented nixtamal (a thermal and alkali-treated maize dough) in water. Although Lactobacillus are the predominant strains in fermented doughs, such as sourdoughs, and non-nixtamalized fermented maize foods, the pozol microbiota is markedly different. This may be the result of the nixtamalization process, which could act as a selective force of some strains. Sii-25124 has been reported as the main amylolytic LAB in pozol; starch is the primary carbon source on nixtamal since monosaccharides and disaccharides are lost during nixtamalization; however, non-amylolytic LAB counts are higher than amylolytic LAB in pozol after 24-h fermentation suggesting that another carbon source is being used by the former bacteria. Hemicellulose (arabinoxylan in maize) becomes available via nixtamalization and is subsequently metabolized by LAB. The aim of this work was to determine whether this bacterium is able to use arabinoxylan as the only carbon source in a defined medium containing arabinoxylan extracted from either nejayote (wash water produced during nixtamal preparation), or beechwood xylan. Xylanase activity in the presence of nejayote arabinoxylan (135.8 ± 48.7 IU/mg protein) was higher than that of beechwood (62.5 ± 19.8 IU/mg protein). Other enzymatic activities, such as arabinofuranosidase and acetyl esterase, were also detected, suggesting the adaptation of the bacterium studied to nixtamal dough. It was concluded that Streptococcus infantarius 25124 isolated from pozol was able to use arabinoxylans, which are present in nixtamal dough, so fermentation does not depend exclusively on free sugars and starch.

Molecular and in vitro assessment of some probiotic characteristics of amylolytic Lactobacillus plantarum strains from Bulgarian fermented products.

In the recent years, consumers' interest in healthy diet opened a new field for functional food development through combining the valuable composition of cereals and the health-promoting properties of lactic acid bacteria (LAB). LAB with amylolytic properties can assimilate starch in a single-step process and could be successfully applied as starter cultures offering an efficient nutritional conversion of cereal matrices. The probiotic potential of amylolytic LAB has not been investigated so far, therefore the present study focused on the molecular screening and in vitro tests of five amylolytic Lactobacillus plantarum strains to assess their tolerance to high acid and bile salts concentrations and antibiotic resistance as basic characteristics required for probiotic strains selection. Results showed excellent correspondence between the genetic screening and the phenotypic tests performed. Survivability at high acidity and bile salts presence was strain specific, with significant positive effect observed for cultures in stationary phase compared to those in exponential phase. Effect of starch in the medium proved most important to ensure viability of the amylolytic strains, which reveals the excellent potential of amylolytic LAB for commercially relevant probiotic applications. The strains proved to be generally safe in terms of antibiotic resistance. Among the five tested strains, L. plantarum Bom2 showed the best probiotic potential.

Effects of Fermentation by Yeast and Amylolytic Lactic Acid Bacteria on Grain Sorghum Protein Content and Digestibility

Despite many advantages to its cultivation, grain sorghum is an underutilized crop because of low nutrient availability, particularly protein digestibility, due to antinutritional compounds in the grain and by moist-heat cooking. Some of these concerns can be mitigated by how the grain is processed. Fermentation is one processing method that can improve digestibility and at the same time concentrate protein in a substrate. In this experiment, grain sorghum was subjected to different treatments and fermented with baker’s yeast (Saccharomyces cerevisiae) and an amylolytic species, Lipomyces kononenkoae, to improve and increase protein content. The effects of pasteurization or sterilization of the substrate, nitrogen supplementation, amyloglucosidase addition, and coculture with Lactobacillus amylovorus were examined. After fermentation, baker’s yeast samples treated with enzyme increased in crude protein, from 9% in unfermented grain to approximately 27% after treatment. Nitrogen supplementation accelerated protein enrichment and was a significant factor at 24 hours of fermentation. Both types of yeast increased pepsin digestibility of sorghum protein compared to thermally processed control samples. The ratio of phytate to protein was reduced by both yeast species. L. kononenkoae reduced phytates in the substrate but did not enrich protein content. The lactic coculture had no significant effect on measured responses.

Molecular structure of cyclomaltodextrinase derived from amylolytic lactic acid bacterium Enterococcus faecium K-1 and properties of recombinant enzymes expressed in Escherichia coli and Lactobacillus plantarum

Gene encoding cyclomaltodextrinase (Cdx) from amylolytic lactic acid bacterium Enterococcus faecium K-1 was cloned and nucleotide sequence was analyzed. The open-reading frame consisted of 1767bp encoding 588 deduced amino acids. Consequently, four typically conserved regions of the glycoside hydrolase family 13 were revealed; however, nine exceeding amino acids (DSYQMTDVP) were found at the 282–290 position in comparison to previously reported cyclomaltodextrinases. This difference is believed to have an influence on the substrate specificity of this enzyme. The recombinant CDases expressed in Escherichia coli BL21 (CDX_E) and Lactobacillus plantarum WCFS1 (CDX_L) with high expression levels of 8041 and 5511U/L were purified by Ni-NTA affinity chromatography. The active form CDX is a dimeric protein with two identical subunits of 62kDa, approximately. Both CDX_E and CDX_L revealed nearly similar properties, but the thermostability of CDX_L was slightly higher. Mn2+ and Co2+ at a concentration of 1mM stimulated the enzyme activity, while the Ag+, Cu2+ and SDS solution completely inhibited enzyme activity. CDX exhibited the highest activity with α-cyclodextrin and β-cyclodextrin, but lower toward pullulan and starch. Importantly, this is the first report describing genes, the molecular structure and properties of cyclomaltodextrinase derived from lactic acid bacteria E. faecium.

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.

Starch utilization routes in lactic acid bacteria: New insight by gene expression assay

The annotation of full genomes of amylolytic lactic acid bacteria (ALAB) leads to conviction that many of them contain a basic pool of chromosomal genes, responsible for starch hydrolysis. However, only the strains that are forced to survive in starchy environment are able to display these genetically determined properties. The aim of the present work is to investigate the genes actually engaged in starch utilization by ALAB using gene transcription assay. Twenty five new ALAB strains, belonging to 11 distinct species of four genera were isolated and analyzed. Among them, the first amylolytic Lactobacillus sakei, Enterococcus faecium, and E. durans were reported. The presence and expression of the genes amy1, glgP, glgB, agl, malL, treC, and dexC were examined. Although all strains possessed extracellular and cell-bound amylase activity and produced lactic acid from starch, high genus and species specificity in the gene expression was observed. ALAB strains of genus Lactobacillus (except L. sakei) and P. acidilactici own and express all the tested genes, while E. faecium and E. durans strains expressed predominantly the gene, encoding amylase. The co-transcription of glgP and glgB genes indicates that glycogen synthesis and starch degradation occur in parallel, which is another example for dual metabolic role of biochemical paths.

Simultaneous saccharification and fermentation (SSF) of jackfruit seed powder (JFSP) to l-lactic acid and to polylactide polymer

A newly isolated amylolytic lactic acid bacterium, Streptococcus equinus, was used for the production of l-lactic acid from jackfruit seed powder (JFSP) by simultaneous saccharification and fermentation (SSF). After optimization of shake flask fermentation by a response surface box-behnken design, the maximum lactate titer was 109g/L from 200g/L jackfruit seed powder. Amberlite IRA67, a weak base resin, was used to recover pure lactic acid from fermented broth and subsequently used for the synthesis of polylactic acid by direct condensation polymerization method with a yield of 62%.

Amylolytic Potential of Lactic Acid Bacteria Isolated from Wet Milled Cereals, Cassava Flour and Fruits

Aims: This research was conducted with the objective to evaluate amylolytic potential of lactic acid bacteria isolated from wet milled cereals, cassava flour and fruits. Methodology: Strains of lactic acid bacteria were isolated from food samples and screened for amylolytic potential using starch hydrolysis technique. The resultant Amylolytic Lactic acid bacteria (ALAB) isolates were then characterized and identified based on their morphological and physiological properties using both conventional methods and API 50CHL kit (Biomerieux, France). These isolates were further evaluated for their amylase yield (U/ml) and amylase activity (mg/ml) using standard procedures. Results: From this study, characteristics typical of the lactic acid bacteria showed that isolates were Gram positive rods, catalase negative, with growth occurring at 30, 37, 40, 45°C and 3, 6, 10% (w/v)NaCl. On the basis of amylolytic potential, only 14 isolates exhibited amylolytic properties with halo diameter of between 25.00 to 68.00 mm. Comparatively, isolates (AMZ5) obtained from maize flour gave the highest amylase potential. Occurrence of the ALAB species

High efficacy bioconversion of starch to lactic acid using an amylolytic lactic acid bacterium isolated from Thai indigenous fermented rice noodles

Amylolytic lactic acid bacterium (ALAB) strain S21 was isolated from Thai indigenous fermented rice noodles and identified as Lactobacillus plantarum, based on 16S rDNA sequence and recA gene analysis. L. plantarum S21 exhibited a specific growth rate (μ) of 0.24 1/h in modified MRS broth containing 10 g/L of starch as the sole carbon source, and a high efficacy in producing lactic acid (9.41, 24.48, 41.84, 74.33, and 94.04 g/L from 10, 25, 50, 75, and 100 g/L of cassava starch, respectively), which are higher values than previously reported for ALAB. Crude amylase from L. plantarum S21 had broad pH stability (3.5–8.0), and hydrolyzed starch to maltose and glucose as the major and minor products. L. plantarum S21 should be considered useful for industrial bioconversion of starch to lactic acid.

Determination of expression and activity of genes involved in starch metabolism in Lactobacillus plantarum A6 during fermentation of a cereal-based gruel

Traditional fermented gruels prepared from cereals are widely used for complementary feeding of young children in Africa and usually have a low energy density. The amylase activity of some lactic acid bacteria (LAB) helps increase the energy content of gruels through partial hydrolysis of starch, thus enabling the incorporation of more starchy material while conserving the desired semi-liquid consistency for young children. Even if this ability is mainly related to the production of alpha-amylase (E.C. 3.2.1.1), in a recent molecular screening, genes coding for enzymes involved in starch metabolism were detected in the efficient amylolytic LAB Lactobacillus plantarum A6: alpha-glucosidase (E.C. 3.2.1.20), neopullulanase (E.C. 3.2.1.135), amylopectin phosphorylase (E.C. 2.4.1.1) and maltose phosphorylase (E.C. 2.4.1.8). The objective of this study was to investigate the expression of these genes in a model of starchy fermented food made from pearl millet (Pennisetum glaucum). Transcriptional and enzymatic analyses were performed during the 18-h fermentation period. Liquefaction was mainly caused by an extracellular alpha amylase encoded by the amyA gene specific to the A6 strain among L. plantarum species and found in both Lactobacillus amylovorus and Lactobacillus manihotivorans. The second most active enzyme was neopullulanase. Other starch metabolizing enzymes were less often detected. The dynamic detection of transcripts of gene during starch fermentation in pearl millet porridge suggests that the set of genes we investigated was not expressed continuously but transiently.

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.