Glutamic Acid Production Research Articles

Biotin concentration affects anaplerotic reactions functioning in glutamic acid production in Corynebacterium glutamicum.

The study investigates the effect of biotin concentration on the role of anaplerotic reactions catalysed by pyruvate carboxylase (PC) and phosphoenolpyruvate carboxylase (PEPC) in glutamic acid production by Corynebacterium glutamicum. C. glutamicum requires biotin for its growth, and its glutamic acid production can be induced by the addition of Tween 40 or penicillin or by biotin limitation. The biotin enzyme PC and the non-biotin enzyme PEPC catalyse two anaplerotic reactions to supply oxaloacetic acid to the TCA cycle in C. glutamicum. Therefore, they are crucial for glutamic acid production in this bacterium. In this study, we investigated the contribution of each anaplerotic reaction to Tween 40- and penicillin-induced glutamic acid production using disruptants of PEPC and PC. In the presence of 20 µg l-1 biotin, which is sufficient for growth, the PEPC-catalysed anaplerotic reaction mainly contributed to Tween 40- and penicillin-induced glutamic acid production. However, when increasing biotin concentration 10-fold (i.e. 200 µg l-1), both PC- and PEPC-catalysed reactions could function in glutamic acid production. Western blotting revealed that the amount of biotin-bound PC was reduced by the addition of Tween 40 and penicillin in the presence of 20 µg l-1. However, these induction treatments did not change the amount of biotin-bound PC in the presence of 200 µg l-1 biotin. These results indicate that both anaplerotic reactions are functional during glutamic acid production in C. glutamicum and that biotin concentration mainly affects which anaplerotic reactions function during glutamic acid production.

Sustainable production of glutamic acid by Enterobacter sp. strain isolated from cheese for potential protein biosynthesis: Optimization by Response Surface Methodology

Glutamic acid (GA), is a very important biomolecule that is widely utilized in food, pharmaceutical, agricultural, medical, and chemical-based industries. The present study utilized acid-treated wheat bran as a carbon source to produce GA. The identified Enterobacter sp. strain BUK_BTE17 MW597320 after screening yield 0.989 g/L GA. The GA production was optimized by CCD of RSM. The effects of independent factors on GA production by Enterobacter sp. were studied. The result obtained indicated a maximum experimental production of 8.451 g/L at the optimized conditions of pH (6), Tempt, (30 °C), substrate conc (6 g/L), and incubation (48 h) was not statistically different from the predicted value of 8.565 g/L at p < 0.05. The G A crystals were examined by TLC, and FTIR which showed the wave numbers of 3268 cm−1, 1640 cm−1, and 2125 cm−1 corresponding to the functional groups CO, NH2, and CH2 for glutamic acid, respectively.

Rational metabolic engineering of Corynebacterium glutamicum for efficient synthesis of L-glutamate

L-glutamic acid is the world's largest bulk amino acid product that is widely used in the food, pharmaceutical and chemical industries. Using Corynebacterium glutamicum G01 as the starting strain, the fermentation by-product alanine content was firstly reduced by knocking out the gene encoding alanine aminotransferase (alaT), a major by-product related to alanine synthesis. Secondly, since the α-ketoglutarate node carbon flow plays an important role in glutamate synthesis, the ribosome-binding site (RBS) sequence optimization was used to reduce the activity of α-ketoglutarate dehydrogenase and enhance the glutamate anabolic flow. The endogenous conversion of α-ketoglutarate to glutamate was also enhanced by screening different glutamate dehydrogenase. Subsequently, the glutamate transporter was rationally desgined to improve the glutamate efflux capacity. Finally, the fermentation conditions of the strain constructed using the above strategy were optimized in 5 L fermenters by a gradient temperature increase combined with a batch replenishment strategy. The glutamic acid production reached (135.33±4.68) g/L, which was 41.2% higher than that of the original strain (96.53±2.32) g/L. The yield was 55.8%, which was 11.6% higher than that of the original strain (44.2%). The combined strategy improved the titer and the yield of glutamic acid, which provides a reference for the metabolic modification of glutamic acid producing strains.

Evaluation of brewer’s spent grain-derived lignocellulosic hydrolysate as a feedstock for amino acid production by submerged fermentation

This study evaluated the potential of utilizing a lignocellulosic hydrolysate from brewer’s spent grain (BSG) as a substrate for amino acid (AA) production by submerged fermentation. The main objective was to explore AA production from BSG hydrolysate using selected microorganisms. Initially, different microorganisms were screened for their growth on BSG hydrolysate, and selected microorganisms were further investigated for AA production by cultivation in shake flasks and bioreactor. From this screening, Saccharomyces cerevisiae and Corynebacterium glutamicum were selected. C. glutamicum produced alanine, proline, valine, and glycine in shake flasks and bioreactor. Highest alanine production (193.6±0.09 mg/L) was found in shake flasks after 30 h while production of proline (22.5±1.03 mg/L), valine (34.8±0.11 mg/L), and glycine (18.7±1.30 mg/L) was highest in bioreactor after 4 h (proline and valine) and 8 h (glycine). To enhance AA production by C. glutamicum, a fed-batch fermentation experiment was performed. Except for glycine, no AAs were produced during the fed-batch phase. S. cerevisiae produced alanine, proline, valine, and glutamic acid in shake flask but not in bioreactor. Highest production of alanine (11.8±1.25 mg/L), proline (11.8±1.06 mg/L), and valine (4.94±1.01 mg/L) was obtained after 50 h while glutamic acid production (66.2±0.49 mg/L) peaked after 60 h. This study demonstrates the production of several AAs from BSG by submerged fermentation; however, further optimization is needed to improve the productivity.

Improved Glutamic Acid Production Capacity of Corynebacterium glutamicum by the ARTP Mutagenesis Method

Glutamic acid is an important amino acid that is used widely in the fields of food, medicine, and agriculture. One of the methods of glutamic acid production is direct microbial fermentation, so the genetic stability and glutamic-acid-producing capacity of the producing strain are the keys to improving glutamic acid concentration. Experiments were carried out using Corynebacterium glutamicum GL−6 as the parental strain, with two iterations of mutagenesis by atmospheric and room temperature plasma (ARTP) and screening with agar plates tolerant to high sugar and malonic acid, and the best strains with stable phenotypes were verified by fermentation in 20 L tanks. The results show that the optimal mutagenesis time of ARTP was 140 s, with lethality and positive mutation rates of 93.0% and 15.6%, respectively. The concentrations of the high-sugar and malonic acid agar plates were 240 g/L and 35 g/L, respectively. A mutant strain, P−45, with improved glutamic acid production capacity and genetic stability, was obtained through two rounds of iterative mutagenesis screening. The concentration of this strain in the Erlenmeyer flasks was 17.7 g/L, which was 18.8% higher than that of the parental strain, GL−6, and could be inherited stably for 10 generations. In the glutamic acid synthesis pathway, the upregulation of the gene encoding citrate synthase (cs), gene encoding isocitrate dehydrogenase (icdh), and gene encoding glutamate dehydrogenase (gdh), and the downregulation of the gene encoding oxoglutarate dehydrogenase complex (odhc) increased the carbon flows of the TCA cycle and its branch metabolic flow to glutamic acid synthesis. P−45 showed a glutamic acid concentration of 147.0 g/L under fed-batch fermentation conditions in 20 L tanks, which was 81.5% higher than the starting strain, GL−6. This study provides a new technical solution for improving microbial metabolites and genetic stability.

Interaction studies of Serendipita indica and Zhihengliuella sp. ISTPL4 and their synergistic role in growth promotion in rice.

Rapid urbanization and globalization demand increasing agricultural productivity. Soil nutrient supply capacity is continuously decreasing due to soil erosion, degradation, salt deposition, undesired element, metal deposition, water scarcity, and an uneven nutrient delivery system. Rice cultivation requires a large amount of water which is becoming detrimental due to these activities. There is a need to increase its productivity. Microbial inoculants are becoming increasingly important in achieving sustainable agricultural production systems. The current study was conducted to investigate the interaction between the root endophytic fungus Serendipita indica (S. indica) and the actinobacterium Zhihengliuella sp. ISTPL4 (Z. sp. ISTPL4) and their synergistic effects on the growth of rice (Oryza sativa L). Both S. indica and Z. sp. ISTPL4 showed positive interactions. Growth of S. indica was observed at different days after Z. sp. ISTPL4 inoculation, and stimulated growth of S. indica was observed when Z. sp. ISTPL4 was inoculated at 5 dafi (days after fungal inoculation). Z. sp. ISTPL4 promoted the growth of S. indica as it increased spore germination. Furthermore, confocal and scanning electron microscopy (SEM) analyses showed a 27% increase in the spore size of S. indica in the presence of Z. sp. ISTPL4. In a liquid chromatography with tandem mass spectrometry (LC-MS/MS) analysis increased production of alanine and glutamic acid was observed in their sequential co-culture as compared with individual cultures. Sequential inoculation of S. indica and Z. sp. ISTPL4 significantly increased the biochemical and physical characteristics of rice as compared with their individual inoculum. Biochemical parameters such as chlorophyll content, total soluble sugar, and flavonoid content in the rice increased by up to 57%, 47%, and 39%, respectively, in the presence of the combined inoculum of S. indica and Z. sp. ISTPL4. This will be the first study, to the best of our knowledge, which shows the fungus and actinobacterium interaction and their synergistic roles in the growth promotion of rice. Furthermore, this novel combination can also be used to boost the growth of other crops to increase the agricultural yield.

Design, synthesis, structure–activity relationship studies, and evaluation of novel GLS1 inhibitors

Glutaminase converts glutamine into glutamic acid and has two isoforms: glutaminase 1 (GLS1) and glutaminase 2 (GLS2). GLS1 is overexpressed in several tumors, and research to develop glutaminase inhibitors as antitumor drugs is currently underway. The present study examined candidate GLS1 inhibitors using in silico screening and attempted to synthesize novel GLS1 inhibitors and assess their GLS1 inhibitory activities in a mouse kidney extract and against recombinant mouse and human GLS1. Novel compounds were synthesized using compound C as the lead compound, and their GLS1 inhibitory activities were evaluated using the mouse kidney extract. Among the derivatives tested, the trans-4-hydroxycyclohexylamide derivative 2j exhibited the strongest inhibitory activity. We also assessed the GLS1 inhibitory activities of the derivatives 2j, 5i, and 8a against recombinant mouse and human GLS1. The derivatives 5i and 8a significantly decreased the production of glutamic acid at 10 mM. In conclusion, we herein identified two compounds that exhibited GLS1 inhibitory activities with equal potencies as known GLS1 inhibitors. These results will contribute to the development of effective novel GLS1 inhibitors with more potent inhibitory activity.

Effect of Carbon Sources on Glutamate Production from Corynebacterium glutamicum 2262

A comparative study between natural and synthetic environments is carried out by realizing six fermentation experiments in batch culture. The objective of this study is to consider the effect of carbon sources on growth and the production of glutamic acid by Corynebacterium glutamicum 2262. The difference between the culture media lies in the carbon source. Two natural environments of date juice, one of which is treated with invertase to hydrolyse sucrose with a concentration of total sugars of 88 g/L. Four synthetic media with a concentration of 34 g/L sugars: medium containing mixed sugars (glucose + fructose + sucrose) with rates proportional to that of date juice, the other three media are composed of a single sugar (either glucose, fructose, or sucrose). The results showed that Corynebacterium glutamicum is able to use the three sugars whether they are single or mixed, although the best results of glutamate production (8.41 g/L) are obtained on the mixture of three sugars, which explains the interest and valorisation of date waste. On the other hand, the date juice-based media are shown to have a glutamate concentration of 7.98 g/L during the hydrolysis of sucrose of date juice.

Optimization of Culture Conditions for L-Glutamic Acid production by Bacillus flexus Using Response Surface Methodology

The body can use L-glutamic acid to make proteins (L-GA). It was formerly derived from plants, however bacteria have subsequently been studied as a potential source of synthesis. Bacillus flexus is a glutamic acid-harvesting bacteria that is well-known. Submerged fermentation was used in the production of L-GA. Response Surface Methodology (RSM) was utilized in this study to statistically optimize fermentation parameters that influence Bacillus flexus yield of L-glutamic acid. The effects of culture conditions, including several medium composition components, were evaluated using Central composite design (CCD) response surface optimization. Inoculum size, pH, substrate concentration, temperature, and time were all found to have substantial effects on glutamic acid production. Production increased considerably (p&lt;0.05). Bacillus flexus produced the highest L-glutamic acid production of 4.9 g/L when the substrate concentration was 6%, the inoculum size was 4%, the temperature was 35°C, the pH was 7, and the time was 3 days, as predicted by RSM. This value is very close to the predicted value of 5.02 g/L, proving its validity. RSM proved to be a powerful strategy for improving this organism's L-glutamic acid synthesis.

Production Of L-Glutamic Acid As A Function Of Urease Activity By Corynebacterium glutamicum X680 Using Agro-Based Raw Materials

Urease catalyzes hydrolysis of urea. The present investigation was undertaken to investigate the urease activity and its optimization during L-glutamic acid fermentation by a biotin auxotroph Corynebacterium glutamicum X680 using urea as the principal nitrogen source. Another interesting part of this study was to investigate the efficiency of this microorganism for utilization of indigenous raw materials (such as hydrolysates of cassava starch, rice bran and wheat bran) as a cheap carbon sources instead of glucose. Among different raw materials, hydrolysate of cassava starch appeared to be the most suitable. However, the production efficiency is significantly less (p&lt;0.01) with cassava starch compared to glucose. When the medium is supplemented with equivalent amount of (10g%) cassava starch hydrolysate, the L-glutamic acid accumulation was reported to be 18.2mg/ml with maximum urease activity (0.18U/mg protein) with pH7 at 300C.Thus, among the different agro-based wastes were examined, cassava starch hydrolysate appeared to be the best alternative of glucose to minimize L- glutamic acid production cost.

Comparative techno-economic assessment of sugarcane biorefineries producing glutamic acid, levulinic acid and xylitol from sugarcane

In this study, six alternative biorefinery scenarios for the production of levulinic acid (LA), glutamic acid (GA) and/or xylitol- or a combination of these chemicals- annexed to an existing sugar mill in 1G-only (molasses feedstock) or integrated 1G2G (molasses and sugar cane lignocellulose feedstock) configurations were simulated in AspenPlus®. Then, mass and energy balances obtained from the simulations were used for the subsequent equipment sizing and costing and to perform the economic performance assessments of the scenarios. All the investigated scenarios were identified as profitable scenarios with the internal rates of return (IRRs) ranging from 21.3%−59.8%. Generally, GA scenarios showed better economic outcomes compared to LA counterparts, attributed to the factors such as higher market prices, higher product throughput and less complicated processing technology which lowers the cost of production. Considering the market size and economic outcome, the 1G GA scenario producing 11.1 t/h GA showed the best economic performance with 59.8% IRR and a minimum product selling price (MSP) of $1687/t. However, a multiproduct facility (1G2G GA-xylitol) can result in more robust economic performance, as a result of implementing xylitol mature technology. Although all investigated scenarios showed profitability potential, life cycle analysis (LCA), social impact assessment and market analysis are required to find out the most sustainable biorefinery option.

RSM‐Based Optimization of Fermentation Conditions and Kinetic Studies of Glutamic Acid and Lysine Production by Corynebacterium glutamicum

Corynebacterium glutamicum is an authenticated microorganism that supports amino acid production consistent with dietary importance. Fermentation parameters like temperature, agitation speed, and carbon source concentration were optimized using response surface methodology. Surface response model suggested that optimal fermentation parameters including 30°C, 50 g/L glucose concentration, and shaking speed of 120 rpm furnished 14.2 g/L of glutamic acid and 5.1 g/L lysine, comparable with the predicted values. After optimizing fermentation parameters in shake flasks, the fermentation kinetics was studied in a stirred fermenter. The kinetic study revealed that the substrate consumption rate achieved a maximum level of 3.36 g/L/hour between 12 and 18 hours; afterwards, it decreased and fell to 1.9 g/L/hour. Average biomass yield over a period of 48 hours was 0.337 g/L; however, maximum biomass yield of 0.51 g/L was noted between 10 and 20 hours. Overall molar yield coefficient of CO2 () was found to be 0.234. The molar yield coefficient of biomass () was 0.6 in exponential phase which decreased afterwards. This study indicates that the average biomass yield over a time of 48 hours was 0.337 g/L, with a maximum yield within 10 to 20 hours obtained under optimized conditions. The molar yield coefficient of CO2 () was found to be 0.234. The molar yield coefficient of biomass () was 0.6 in exponential phase which decreased and fell to near zero at 48 hrs.

Induction of glutamic acid production by copper in Corynebacterium glutamicum.

From the previous transcriptome analysis (Hirasawa et al. Biotechnol J 13:e1700612, 2018), it was found that expression of genes whose expression is regulated by stress-responsive transcriptional regulators was altered during penicillin-induced glutamic acid production in Corynebacterium glutamicum. Therefore, we investigated whether stress treatments, such as copper and iron addition, could induce glutamic acid production in C. glutamicum and found that the addition of copper did induce glutamic acid production in this species. Moreover, we also determined that glutamic acid production levels upon copper addition in a gain-of-function mutant strain of the mechanosensitive channel, NCgl1221, involved in glutamic acid export, were comparable to glutamic acid levels produced upon penicillin addition and biotin limitation in the wild-type strain. Furthermore, disruption of the odhI gene, which encodes a protein responsible for the decreased activity of the 2-oxoglutarate dehydrogenase complex during glutamic acid production, significantly diminished glutamic acid production induced by copper. These results indicate that copper can induce glutamic acid production and this induction requires OdhI like biotin limitation and penicillin addition, but a gain-of-function mutation in the NCgl1221 mechanosensitive channel is necessary for its high-level glutamic acid production. However, a significant increase in odhI transcription was not observed with copper addition in both wild-type and NCgl1221 gain-of-function mutant strains. In addition, disruption of the csoR gene encoding a copper-responsive transcriptional repressor enhanced copper-induced glutamic acid production in the NCgl1221 gain-of-function mutant, indicating that unidentified CsoR-regulated genes may contribute to copper-induced glutamic acid production in C. glutamicum. KEY POINTS: • Copper can induce glutamic acid production by Corynebacterium glutamicum. • Copper-induced glutamic acid production requires OdhI protein. • Copper-induced glutamic acid production requires a gain-of-function mutation in the mechanosensitive channel NCgl1221, which is responsible for the production of glutamic acid.

Application of RSM for optimization of glutamic acid production by Corynebacterium glutamicum in bath culture

Glutamate plays an important role in different cellular processes. Its new applications in various industries have led to an increase in the production of it while fermentation is a very important economically method. In this study, the production of glutamate by the wild type of Corynebacterium glutamicum PTCC(Persian Type Culture Collection) 1532 was optimized using RSM.Central Composite Design (CCD) was developed by Design-Expert software version 12.0.3.0 (dx-12, State-Ease Inc.) to evaluate the effect of four important variables in five levels on glutamate production. TLC was employed to evaluate glutamate in medium qualitatively and then quantitative estimation was done by HPLC.Normal probability analysis demonstrated that data has a normal distribution. The results of ANOVA analysis showed that the urea concentration both alone and with temperature is the most effective variable in the fermentation process. Based on the quadratic model obtained in CCD, temperature 30 °C; glucose 9 g.dL−1; biotin 9 μg.L−1 and urea concentration of 0.3 g.dL−1 were found optimum conditions with a predicted glutamate production of 19.84 mg.mL−1 with desirable level 1.Therefore RSM can be an effective method to optimize glutamate production and the findings of this study are a guideline for the other amino acids fermentation by C. glutamicum.

Molecular characterization of a novel aspartyl aminopeptidase that contributes to the increase in glutamic acid content in chicken meat during cooking

The enzyme involved in the increase in glutamic acid content in chicken meat during cooking was identified and characterized. Chicken homogenate produced significantly more free glutamic acid and exhibited higher glutamyl p-nitroanilide (Glu-pNA) hydrolyzing activity than beef when heat cooked. Amino acid sequencing revealed the presence of aspartyl aminopeptidase (DNPEP) in chicken meat. Using RT-PCR, DNPEP gene expression was detected in chicken breast and thigh muscles, liver, and small intestine, together with various other peptidase genes. Full-length DNPEP cDNA was cloned, and recombinant chicken DNPEP (cDNPEP) was expressed in Escherichia coli. cDNPEP showed five-fold higher activity against Glu-pNA than against aspartyl-pNA, which represents a different substrate specificity than observed for recombinant bovine DNPEP (bDNPEP). The Km values of both DNPEPs with Glu p-NA substrates indicated a higher affinity of cDNPEP for glutamyl residues. This unique substrate specificity of cDNPEP contributes to efficient glutamic acid production in chickens.

Genetic Background Behind the Amino Acid Profiles of Fermented Soybeans Produced by Four Bacillus spp.

Strains of four Bacillus spp. were respectively inoculated into sterilized soybeans and the free amino acid profiles of the resulting cultures were analyzed to discern their metabolic traits. After 30 days of culture, B. licheniformis showed the highest production of serine, threonine, and glutamic acid; B. subtilis exhibited the highest production of alanine, asparagine, glycine, leucine, proline, tryptophan, and lysine. B. velezensis increased the γ-aminobutyric acid (GABA) concentration to >200% of that in the control samples. B. sonorensis produced a somewhat similar amino acid profile with B. licheniformis. Comparative genomic analysis of the four Bacillus strains and the genetic profiles of the produced free amino acids revealed that genes involved in glutamate and arginine metabolism were not common to the four strains. The genes gadA/B (encoding a glutamate decarboxylase), rocE (amino acid permease), and puuD (γ-glutamyl-γ-aminobutyrate hydrolase) determined GABA production, and their presence was species-specific. Taken together, B. licheniformis and B. velezensis were respectively shown to have high potential to increase concentrations of glutamic acid and GABA, while B. subtilis has the ability to increase essential amino acid concentrations in fermented soybean foods.

Selection of Lactococcus lactis HY7803 for Glutamic Acid Production Based on Comparative Genomic Analysis.

Comparative genomic analysis was performed on eight species of lactic acid bacteria (LAB)-Lactococcus (L.) lactis, Lactobacillus (Lb.) plantarum, Lb. casei, Lb. brevis, Leuconostoc (Leu.) mesenteroides, Lb. fermentum, Lb. buchneri, and Lb. curvatus-to assess their glutamic acid production pathways. Glutamic acid is important for umami taste in foods. The only genes for glutamic acid production identified in the eight LAB were for conversion from glutamine in L. lactis and Leu. mesenteroides, and from glucose via citrate in L. lactis. Thus, L. lactis was considered to be potentially the best of the species for glutamic acid production. By biochemical analyses, L. lactis HY7803 was selected for glutamic acid production from among 17 L. lactis strains. Strain HY7803 produced 83.16 pmol/μl glutamic acid from glucose, and exogenous supplementation of citrate increased this to 108.42 pmol/μl. Including glutamic acid, strain HY7803 produced more of 10 free amino acids than L. lactis reference strains IL1403 and ATCC 7962 in the presence of exogenous citrate. The differences in the amino acid profiles of the strains were illuminated by principal component analysis. Our results indicate that L. lactis HY7803 may be a good starter strain for glutamic acid production.

Influence of Dietary Supplementation for Hyperhomocysteinemia Treatments.

Hyperhomocysteinemia is recognized as risk factor for cardiovascular and age-associated diseases. Folic acid supplementation efficiently lowers plasma homocysteine (Hcy) levels, but high intake may negatively affect health because of unnatural levels of unmetabolized folic acid in the systemic circulation. Oxoproline (Oxo) provides by glutamic acid production an increase of intracellular folic acid trapping. Aim of this study was to compare the efficacy of three supplementation protocols: (1) traditional therapy (5-methyl-tetrahydrofolate: 15 mg/day); (2) 5 mL/day of Oxo with 300 μg folic acid (oxifolic); (3) 5 mL/day of Oxo alone (magnesio+) in a 90 days randomized trial on thirty-two moderate hyperhomocysteinemic (18.6 ± 2.4 μmol·L−1) patients (age 48 ± 14 years). Thiols: cysteine (Cys), cysteinylglycine (Cys–Gly) and glutathione levels were assessed too. Every supplementation induced significant (p range <0.05–0.0001) reductions of Hcy level and Cys concentration after the three protocols adopted. Otherwise glutathione concentration significantly increased after oxifolic (p < 0.01) and traditional (p < 0.05) supplementation. The integration of Oxo resulted an interesting alternative to traditional therapy because absence or minimal number of folates in the integrator eliminates any chance of excess that can constitute a long-term risk.

High-Titer Glutamic Acid Production from Lignocellulose Using an Engineered Corynebacterium glutamicum with Simultaneous Co-utilization of Xylose and Glucose

Xylose utilization by Corynebacterium glutamicum is an essential but unresolved issue in glutamic acid production from lignocellulose biomass. Co-existence of xylose with inhibitors requires a sele...

Optimization of glutamic acid production by Corynebacterium glutamicum using response surface methodology

The body to build proteins can use l-Glutamic acid (l-GA). Earlier it was obtained from plant sources, later on microbes have been explored for the production. Corynebacterium glutamicum is a prominent organism used to harvest the glutamic acid. Submerged fermentation was adopted for l-GA production. Various nitrogen/carbon substrates used to find out the best nitrogen and carbon source. Statistical methods especially RSM (response surface method) stayed employed for the effect of various factors such as inoculum size, urea, glucose and salt on the l-GA production. As per the preliminary studies, urea and glucose were chosen as carbon and nitrogen sources. Further, the optimum values have been maximally documented in the glucose (50 g/L), then urea (10 g/L), 19.24% of salt solution and 5% of inoculum size. Maximum Yield of l-GA is produced through RSM-16.49 g/L. The experimental l-Glutamic acid production was 16.36 g/L at an optimum condition that compared well to the maximum predicted values by RSM (16.499 g/L). Non-linear regression quadratic model was developed for the l-GA synthesis; the methodology was validated statistically and the determination coefficient (R2) was found to be 0.991. Thus the study identified the potential carbon and nitrogen source for a higher yield for l-GA using C. glutamicum under submerged fermentation and also this method minimizes the time for optimizing the medium components statistically.