Optimization of glucoamylase production by Colletotrichum sp. KCP1 using statistical methodology

Application of statistical methodology for the optimization of L-glutaminase enzyme production from Streptomyces pseudogriseolus ZHG20 under solid-state fermentation

BACKGROUND

Actinomycetes are excellent microbial sources for various chemical structures like enzymes, most of which are used in pharmaceutical and industrial products. Actinomycetes are preferred sources of enzymes due to their high ability to produce extracellular enzymes. L-glutaminase has proven its essential role as a pharmaceutical agent in cancer therapy and an economic agent in the food industry. The current study aimed to screen the potent L-glutaminase producer and optimize the production media for maximum enzyme yield using one factor at a time (OFAT) approach and statistical approaches under solid-state fermentation (SSF).

RESULTS

Out of 20 actinomycetes strains isolated from rhizosphere soil, 5 isolates produced extracellular L-glutaminase. One isolate was chosen as the most potent strain, and identified as Streptomyces pseudogriseolus ZHG20 based on 16S rRNA. The production and optimization process were carried out under SSF, after optimization using OFAT method, the enzyme production increased up to 884.61 U/gds. Further, statistical strategy, response surface methodology (RSM), and central composite design (CCD) were employed for the level optimization of significant media component (p < 0.05), i.e., wheat bran, sesame oil cake, and corn steep liquor which are leading to increase 3.21-fold L-glutaminase production as compared to unoptimized media.

CONCLUSIONS

The presented investigation reveals the optimization of various physicochemical parameters using OFAT and RSM-CCD. Statistical approaches proved to be an effective method for increasing the yield of extracellular L-glutaminase from S. pseudogriseolus ZHG20 where L-glutaminase activity increased up to 1297.87 U/gds which is 3.21-fold higher than the unoptimized medium using a mixture of two solid substrates (wheat bran and sesame oil cake) incubated at pH 7.0 for 6 days at 33 °C.

Utilization of agro-industrial waste for β-galactosidase production under solid state fermentation using halotolerant Aspergillus tubingensis GR1 isolate

A halotolerant fungal isolate Aspergillus tubingensis GR1 was isolated from the man-made solar saltern located at Khambhat, Gujarat, India, and identified using 28S rDNA partial genome sequencing. This isolate was studied for β-galactosidase production under solid state fermentation using wheat bran and deproteinized acid cheese whey. The influence of various agro-industrial wastes, nitrogen source and other growth conditions on β-galactosidase production was investigated using 'one-factor-at-a-time' approach. Among various variables screened along with wheat bran and deproteinized acid cheese whey as major growth substrate, corn steep liquor and MgSO₄ were found to be most significant. The optimum concentrations of these significant parameters were determined employing the response surface central composite design, revealing corn steep liquor concentration (2 mL) and magnesium sulphate (50 mg) per 5 g of wheat bran and 20 mL of deproteinized acid cheese whey for highest enzyme production (15,936 U/gds). These results suggest the feasibility of industrial large-scale production of β-galactosidase known to be valuable in whey hydrolysis and removal of galactosyl residue from polysaccharide.

A statistical approach for the production of thermostable and alklophilic alpha-amylase from Bacillus amyloliquefaciens KCP2 under solid-state fermentation

The bacterial strain producing thermostable, alklophilic alpha-amylase was identified as Bacillus amyloliquefaciens KCP2 using 16S rDNA gene sequencing data (NCBI Accession No: KF112071). Medium components were optimized through the statistical approach for the synthesis of alpha-amylase by the organism under solid-state fermentation using wheat bran as the substrate. The medium components influencing the enzyme production were identified using a two-level fractional factorial Plackett–Burman design. Among the various variables screened, starch, ammonium sulphate and calcium chloride were found to be most significant medium components. The optimum levels of these significant parameters were determined employing the response surface Central Composite design which significantly increased the enzyme production with the supplementation of starch 0.01 g, ammonium sulphate 0.2 g and 5 mM calcium chloride in the production medium. Temperature and pH stability of the alpha-amylase suggested its wide application in the food and pharmaceutical industries.

Application of Statistically Based Experimental Designs to Optimize Cellulase Production and Identification of Gene

A natural bacterial strain identified as Bacillus amyloliquefaciens MBAA3 using 16S rDNA partial genome sequencing has been studied for optimization of cellulase production. Statistical screening of media components for production of cellulase by B. amyloliquefaciens MBAA3 was carried out by Plackett-Burman design. Plackett-Burman design showed CMC, MgSO4 and pH as significant components influencing the cellulase production from the media components screened by Plackett-Burman fractional factorial design. The optimum concentrations of these significant parameters were determined employing the response surface central composite design, involving three factors and five levels was adopted to acquire the best medium for the production of cellulase enzyme revealed concentration of CMC (1.84 g), MgSO4 (0.275 g), and pH (8.5) in media for highest enzyme production. Response surface counter plots revealed that middle level of MgSO4 and middle level of CMC, higher level of CMC and lower level of pH and higher level of MgSO4 with lower level of pH increase the production of cellulase. After optimization cellulase activity increased by 6.81 fold. Presence of cellulase gene in MBAA3 was conformed by the amplification of genomic DNA of MBAA3. A PCR product of cellulase gene of 1500 bp was successfully amplified. The amplified gene was conformed by sequencing the amplified product and sequence was deposited in the gene bank under the accession number KF929416. Response surface graph showing interaction effects between concentration of a CMC and MgSO4. b pH and CMC. c MgSO4 and pH.

Sequential Statistical Optimization of Media Components for the Production of Glucoamylase by Thermophilic Fungus Humicola grisea MTCC 352

Glucoamylase is an industrially important enzyme which converts soluble starch into glucose. The media components for the production of glucoamylase from thermophilic fungus Humicola grisea MTCC 352 have been optimized. Eight media components, namely, soluble starch, yeast extract, KH2PO4, K2HPO4, NaCl, CaCl2, MgSO4 ·7H2O, and Vogel's trace elements solution, were first screened for their effect on the production of glucoamylase and only four components (soluble starch, yeast extract, K2HPO4, and MgSO4 ·7H2O) were identified as statistically significant using Plackett-Burman design. It was fitted into a first-order model (R (2) = 0.9859). Steepest ascent method was performed to identify the location of optimum. Central composite design was employed to determine the optimum values (soluble starch: 28.41 g/L, yeast extract: 9.61 g/L, K2HPO4: 2.42 g/L, and MgSO4 ·7H2O: 1.91 g/L). The experimental activity of 12.27 U/mL obtained was close to the predicted activity of 12.15. High R (2) value (0.9397), low PRESS value (9.47), and AARD values (2.07%) indicate the accuracy of the proposed model. The glucoamylase production was found to increase from 4.57 U/mL to 12.27 U/mL, a 2.68-fold enhancement, as compared to the unoptimized medium.

Statistical optimization and anticancer activity of a red pigment isolated from Streptomyces sp. PM4

OBJECTIVE

To enhance the pigment production by Streptomyces sp. PM4 for evaluating its anticancer activity.

METHODS

Response surface methodology was employed to enhance the production of red pigment from Streptomyces sp. PM4. Optimized pigment was purified and evaluated for the anticancer activity against HT1080, Hep2, HeLa and MCF7 cell lines by MTT assay.

RESULTS

Based on the response surface methodology, it could be concluded that maltose (4.06 g), peptone (7.34 g), yeast extract (4.34 g) and tyrosine (2.89 g) were required for the maximum production of pigment (1.68 g/L) by the Streptomyces sp. PM4. Optimization of the medium with the above tested features increased the pigment yield by 4.6 fold. Pigment showed the potential anticancer activity against HT1080, HEp-2, HeLa and MCF-7 cell lines with the IC50 value of 18.5, 15.3, 9.6 and 8.5 respectively.

CONCLUSIONS

The study revealed that the maximum amount of pigment could be produced to treat cancer.

Kinetic and Thermodynamic Characterization of Glucoamylase from Colletotrichum sp. KCP1

Extracellular glucoamylase of Colletotrichum sp. KCP1 produced through solid state fermentation was purified by two steps purification process comprising ammonium sulphate precipitation followed by gel permeation chromatography (GPC). The Recovery of glucoamylase after GPC was 50.40 % with 19.3-fold increase in specific activity. The molecular weight of enzyme was found to be 162.18 kDa by native-PAGE and was dimeric protein of two sub-units with molecular weight of 94.62 and 67.60 kDa as determined by SDS-PAGE. Activation energy for starch hydrolysis was 26.45 kJ mol(-1) while temperature quotient (Q 10 ) was found to be 1.9. The enzyme was found to be stable over wide pH range and thermally stable at 40-50 °C up to 120 min while exhibited maximum activity at 50 °C with pH 5.0. The pKa1 and pKa2 of ionisable groups of active site controlling V max were 3.5 and 6.8, respectively. V max , K m and K cat for starch hydrolysis were found to be 58.82 U ml(-1), 1.17 mg (starch) ml(-1) and 449 s(-1), respectively. Activation energy for irreversible inactivation (E a(d)) of glucoamylase was 74.85 kJ mol(-1). Thermodynamic parameters of irreversible inactivation of glucoamylase and starch hydrolysis were also determined.