Response surface optimization of cellulase production by Aspergillus stellatus NFCCI 5299 in shake flask submerged fermentation using wheat bran

The expense of cellulase enzymes is the main barrier to the enzymatic saccharification of biomass. Numerous tactics, such as the utilizing inexpensive lignocellulosic substrates as well as economically feasible fermentation techniques for the production of the enzyme may reduce the cost of cellulases. The present investigation was aimed to improve cellulase production employing potential cellulolytic soil fungi, Aspergillus stellatus NFCCI 5299 using wheat bran as substrate. Employing response surface methodology (RSM) with central composite design (CCD), the most efficient process parameters were determined. The ideal conditions for the synthesis of carboxy methyl cellulase (CMCase) and filter paper cellulase activity (FPase) were 6 days of incubation, inoculum size of 4 mycelial disc, 125 rpm of agitation, and 3.5% of wheat bran. The significant mycelial development and enzymatic digestion of wheat bran were discovered by scanning electron microscopy (SEM) and fourier transform infrared (FTIR) analysis. The findings suggested that it can be practicable to use wheat bran as substrate under submerged fermentation utilizing Aspergillusstellatus NFCCI 5299 for efficient cellulase production.

The Combined Cultivation of Feruloyl Esterase-Producing Strains with CMCase and Xylanase-Producing Strains Increases the Release of Ferulic Acid

Feruloyl esterase (FAE)-producing micro-organisms to obtain ferulic acid (FA) from natural substrates have good industrial prospects, and the synergistic effect of multiple bacteria can better improve the yield of FA. In this study, on the premise of the synergistic effect of FAE, hemicellulose, and cellulase, the key strain Klebsiella oxytoca Z28 with FAE was combined with CMCase and Xylanase-producing strains to produce FA. The combination of strains with higher FA production are Klebsiella oxytoca Z28, Klebsiella pneumoniae JZE, Bacillus velezensis G1, and their FA production can reach 109.67 μg/g, which is 15% higher than that of single bacteria. To explore the effects of temperature, Ph, inoculum amount, distillers grains concentration and fermentation time on the FAE activity of the combination of strains in the fermentation process, and determined that temperature, Ph, and fermentation time were the main influencing factors and optimized through orthogonal design. The optimized fermentation conditions are 34 °C, Ph 8.0, and fermentation days for 6 days, the FAE activity can reach 270.78 U/L, and the FA yield of the combined strain is 324.50 μg/g, which is 200% higher than that of single-strain fermentation.

A novel Trichoderma reesei mutant RP698 with enhanced cellulase production

A new strain of Trichoderma reesei (teleomorph Hypocrea jecorina) with high cellulase production was obtained by exposing the spores from T. reesei QM9414 to an ultraviolet light followed by selecting fast-growing colonies on plates containing CMC (1% w/v) as the carbon source. The mutant T. reesei RP698 reduced cultivation period to 5 days and increased tolerance to the end-products of enzymatic cellulose digestion. Under submerged fermentation conditions, FPase, CMCase, and Avicelase production increased up to 2-fold as compared to the original QM9414 strain. The highest levels of cellulase activity were obtained at 27 °C after 72 h with Avicel®, cellobiose, and sugarcane bagasse as carbon sources. The temperature and pH activity optima of the FPase, CMCase, and Avicelase were approximately 60 °C and 5.0, respectively. The cellulase activity was unaffected by the addition of 140 mM glucose in the enzyme assay. When T. reesei RP698 crude extract was supplemented by the addition of β-glucosidase from Scytalidium thermophilum, a 2.3-fold increase in glucose release was observed, confirming the low inhibition by the end-product of cellulose hydrolysis. These features indicate the utility of this mutant strain in the production of enzymatic cocktails for biomass degradation.

Effect of Different Carbon Sources on Cellulase Production by Marine Strain Microbulbifer hydrolyticus IRE-31-192

Cellulase is an important enzyme that can be used to breakdown lignocellulose into glucose. Microbulbifer hydrolyticus IRE-31(ATCC 700072) is a kind of marine bacterium, which could grow in high salinity medium and has fast-strong growth ability. In this study, a novel strain was screened from Microbulbifer hydrolyticus IRE-31 through mutations to produce cellulase. The effect of different carbon sources on the growth as well as on the production of cellulase of the new strain was studied. Carboxymethyl-cellulase (CMCase) activity selected to represent cellulase was proven to be effectively promoted while xylose, galactose, and melibiose as well as glucose were used as carbon sources. When xylose and glucose were chosen to be further investigated, 472.57 U/L and 266.01 U/L CMCase activity were obtained from 30 g/L glucose and 10 g/L xylose, respectively. These results clarified the effect of different carbon sources on the production of cellulase, which laid a good foundation for the further research in the production of cellulase by marine bacteria.

Prospecting of soybean hulls as an inducer carbon source for the cellulase production

Cellulases constitute an enzymatic complex involved in the cellulose hydrolysis β-1, 4-glycosidic linkages to release of glucose. Therefore, its application to degrade agro-industrial residues becomes relevant, since glucose is a product of industrial interest, aiming at its conversion into biocommodity production (e.g., enzymes, bioethanol and other value-added biochemicals). Thus, in natura Soybean hulls as well as fractions obtained from its alkaline, autohydrolysis and organosolv pretreatments were used as carbon sources in submerged fermentation processes to evaluate the cellulase-inducing capacity using a Penicillium sp. strain. Results showed an inductive effect on the production of 0.130 and 0.066 U/mL for CMCase and FPase, respectively, using 1% of the in natura residue. Regarding the fraction obtained from soybean hulls pretreated by autohydrolysis and organosolv, avicelase and β-Glucosidase displayed a production of 0.200 and 0.550 U/mL, respectively. Therefore, the use of pretreated Soybean hull revealed its potential as an alternative carbon source for the cellulase production, which may contribute significantly to biotechnological purposes by adding value to an agro-industrial residue.

Augmented cellulase production by Bacillus subtilis strain MU S1 using different statistical experimental designs

The production of cellulase by Bacillus subtilis MU S1, a strain isolated from Eravikulam National Park, was optimized using one-factor-at-a-time (OFAT) and statistical methods. Physical parameters like incubation temperature and agitation speed were optimized using OFAT and found to be 40 °C and 150 rpm, respectively, whereas, medium was optimized by statistical tools. Plackett-Burman design (PBD) was employed to screen the significant variables that highly influence cellulase production. The design showed carboxymethyl cellulose (CMC), yeast extract, NaCl, pH, MgSO4 and NaNO3 as the most significant components that affect cellulase production. Among these CMC, yeast extract, NaCl and pH showed positive effect whereas MgSO4 and NaNO3 were found to be significant at their lower levels. The optimum levels of the components that positively affect enzyme production were determined using response surface methodology (RSM) based on central composite design (CCD). Three factors namely CMC, yeast extract and NaCl were studied at five levels whilst pH of the medium was kept constant at 7. The optimal levels of the components were CMC (13.46 g/l), yeast extract (8.38 g/l) and NaCl (6.31 g/l) at pH 7. The maximum cellulase activity in optimized medium was 566.66 U/ml which was close to the predicted activity of 541.05 U/ml. Optimization of physical parameters and medium components showed an overall 3.2-fold increase in activity compared to unoptimized condition (179.06 U/ml).

Production and characterization of an acido-thermophilic, organic solvent stable cellulase from Bacillus sonorensis HSC7 by conversion of lignocellulosic wastes

The acidophilic and thermophilic cellulase would facilitate the conversion of lignocellulosic biomass to biofuel. In this study, Bacillus sonorensis HSC7 isolated as the best thermophilic cellulose degrading bacterium from Gorooh hot spring. 16S rRNA gene sequencing showed that, this strain closely related to the B. sonorensis. CMCase production was considered under varying environmental parameters. Results showed that, sucrose and (NH4)2SO4 were obtained as the best carbon and nitrogen sources for CMCase production. B. sonorensis HSC7 produced CMCase during the growth in optimized medium supplemented with agricultural wastes as sole carbon sources. The enzyme was active with optimum temperature of 70 °C and the optimum CMCase activity and stability observed at pH 4.0 and 5.0, respectively. These are characteristics indicating that, this enzyme could be an acidophilic and thermophilic CMCase. Furthermore, the CMCase activity improved by methanol (166%), chloroform (152%), while it was inhibited by DMF (61%). The CMCase activity was enhanced in the presence of Mg+2 (110%), Cu+2 (116%), Triton X-100 (118%) and it retained 57% of its activity at 30% NaCl. The compatibility of HSC7 CMCase varied for each laundry detergent, with higher stability being observed in the presence of Taj® and darya®. This enzyme, that is able to work under extreme conditions, has potential applications in various industries.

Characterization and phylogenetic diversity of carboxymethyl cellulase producing bacillus species from a landfill ecosystem

Total population of cellulose degrading bacteria was studied in a landfill ecosystem as a part of microbial diversity study. Samples were obtained from 3 and 5 feet depth of a local landfill being operated for past 10 years. Among many isolates, 22 bacterial strains were selected based on their capability to decompose carboxymethyl cellulose (CMC). These isolates were cultivated on agar medium with CMC as the carbon source. All isolates were Gram positive, endospore forming and alkalophilic bacteria with optimum growth pH 9-10. They were grouped based on the phenotypic and chemotaxonomic characters and representative strains of different groups along with high carboxymethyl cellulase (CMCase) producing strains were included for further characterization. Analysis of 16S rRNA gene indicated that these strains belong to different species of the genus Bacillus. Maximum CMCase activity of 4.8 U/ml at 50°C was obtained by strain LFC15. Results in the present study indicated the potential of waste land ecosystems such as landfill are potential source for isolation of industrially important microorganisms.