Optimal Conditions For Maximum Production Research Articles

Statistical bioprocess optimization for enhanced production of a thermo alkalophilic polygalacturonase (PGase) from Pseudomonas sp. 13156349 using solid substrate fermentation (SSF)

In this study, a polygalacturonase (PGase) producing bacterial strain was isolated and identified as Pseudomonas sp. 13159349 from fruit market soils, and TLC analysis confirmed its pectinolytic activity. Additionally, SSF, Plackett-Burman design (PB), and response surface methodology (RSM) were used to optimize the production of this thermostable and alkalophilic PGase. Wheat bran demonstrated the highest activity (60.13 ± 3.39 U/gm) among the various agricultural wastes used as solid substrates. To further enhance the enzyme production, statistical optimization of media components was investigated using the PB design. Among the 11 variables tested, pH (p < 0.0001), inoculum size (p < 0.0001), incubation time (p < 0.0001), and temperature (p < 0.0041) were found to have a positive effect on the production. The interaction and concentration of the selected factors were examined by RSM, which demonstrated the optimal conditions for maximum production (315.65 U/gm) of the enzyme using wheat bran as the solid substrate were pH 10.5, 61–66 h of incubation, and 6–7.5% inoculum size. The model was highly significant, with a p-value of <0.0001, an F-value of 95.33, and a low CV of 2.31. The RSM model was validated by a laboratory-scale experiment showing 30600 ± 400.32 U/100 gm PGase activity. Thus, SSF and the statistical design of media components resulted in a significant 5.2-fold increase in PGase output solely by using agro waste and optimizing the physical parameters, making this a highly cost-effective bioprocess.

Improved production of antioxidant-phenolic compounds and certain fungal phenolic-associated enzymes under solid-state fermentation of chia seeds with Trichoderma reesei: response surface methodology-based optimization

Chia seeds (CS) are becoming increasingly consumed due to their great nutritional and therapeutic properties. In this study, solid-state fermentation (SSF) of CS by Trichoderma reesei was employed to maximize the production of the antioxidant-phenolic compounds and some fungal phenolic-associated enzymes (α-amylase, xylanase, β-glucosidase, polygalacturonase, and phenylalanine ammonia-lyase). The SSF-conditions were statistically optimized using response surface methodology (RSM). In the statistical model, four variables were analyzed at two levels. According to RSM, the adjusted R2 (< 0.9) is reasonably consistent with the predicted R2 (< 0.9), indicating that the statistical model is valid. The optimal conditions for maximum production of both phenolic compounds and fungal phenolic-associated enzymes were found to be 28 °C, pH 7.0, 20% moisture, and 7-day fermentation. The total phenolic content of fermented CS (FCS) increased 23 folds and total antioxidant activity was enhanced by 113- and 150-fold using DPPH and ABTS methods, respectively. Three new phenolics (kaempferol, apigenin, and p-coumaric) were recognized in FCS using HPLC analysis. The activities of all the extracted phenolic-associated enzymes showed strong correlations with the phenolic content of FCS. Against some human-pathogenic bacteria, FCS extract displayed considerably better antibacterial activity than UFCS extract. Finally, the phenolic-rich-FCS can be employed as a dietary supplement as well as an antibacterial agent. Furthermore, T. reesei has produced considerable quantities of industrially valuable enzymes.

Pilot scale production of recombinant hemicellulases and their saccharification potential

Synergistic saccharification ability of hemicellulases (endo-xylanase and β-xylosidase) was evaluated in this study for the bioethanol production from plant biomass. Endo-xylanase and β-xylosidase genes from Bacillus licheniformis were cloned and expressed in Escherichia coli BL21 (DE3). Maximum endo-xylanase production was obtained at 200 rpm agitation speed, air supply rate 2.0 vvm, 70% volume of the medium, 20% dissolved oxygen level and with 3% inoculum size. The optimal conditions for maximum production of recombinant β-xylosidase enzyme at pilot scale were 200 rpm agitation speed, 25% dissolved oxygen level, 2.5 vvm aeration rate, 70% volume of the medium with 2% inoculum size. Furthermore, the saccharification potential of these recombinant enzymes was checked for the production of xylose sugar by bioconversion of plant biomass by optimizing individually as well as synergistically by optimizing various parameters. Maximum saccharification (93%) of plant biomass was observed when both enzymes were used at a time with 8% sugarcane bagasse as a substrate and 200 units of each enzyme after incubation of 6 hr at 50 °C and 120 rpm. The results obtained in this study suggested these recombinant hemicellulases as potential candidates for the conversion of complex agricultural residues into simple sugars for ultimate use in the biofuel industry.

Statistical Optimization of the Physico-Chemical Parameters for Pigment Production in Submerged Fermentation of Talaromyces albobiverticillius 30548.

Talaromyces albobiverticillius 30548 is a marine-derived pigment producing filamentous fungus, isolated from the La Réunion island, in the Indian Ocean. The objective of this study was to examine and optimize the submerged fermentation (SmF) process parameters such as initial pH (4–9), temperature (21–27 °C), agitation speed (100–200 rpm), and fermentation time (0–336 h), for maximum production of pigments (orange and red) and biomass, using the Box–Behnken Experimental Design and Response Surface Modeling (BBED and RSM). This methodology allowed consideration of multifactorial interactions between a set of parameters. Experiments were carried out based on the BBED using 250 mL shake flasks, with a 100 mL working volume of potato dextrose broth (PDB). From the experimental data, mathematical models were developed to predict the pigments and biomass yields. The individual and interactive effects of the process variables on the responses were also investigated (RSM). The optimal conditions for maximum production of pigments and biomass were derived by the numerical optimization method, as follows—initial pH of 6.4, temperature of 24 °C, agitation speed of 164 rpm, and fermentation time of 149 h, respectively.

Isolation and Characterization of a Nitrile-Hydrolysing Bacterium Isoptericola variabilis RGT01.

A nitrile-hydrolysing bacterium, identified as Isoptericola variabilis RGT01, was isolated from industrial effluent through enrichment culture technique using acrylonitrile as the carbon source. Whole cells of this microorganism exhibited a broad range of nitrile-hydrolysing activity as they hydrolysed five aliphatic nitriles (acetonitrile, acrylonitrile, propionitrile, butyronitrile and valeronitrile), two aromatic nitriles (benzonitrile and m-Tolunitrile) and two arylacetonitriles (4-Methoxyphenyl acetonitrile and phenoxyacetonitrile). The nitrile-hydrolysing activity was inducible in nature and acetonitrile proved to be the most efficient inducer. Minimal salt medium supplemented with 50mM acetonitrile, an incubation temperature of 30°C with 2% v/v inoculum, at 200rpm and incubation of 48h were found to be the optimal conditions for maximum production (2.64±0.12 U/mg) of nitrile-hydrolysing activity. This activity was stable at 30°C as it retained around 86% activity after 4h at this temperature, but was thermolabile with a half-life of 120min and 45min at 40°C and 50°C respectively.

PLS-based kinetics modeling and optimization of the oxidative coupling of methane over Na2WO4/Mn/SiO2 catalyst

Reactor modeling for the oxidative coupling of methane over Na2WO4/Mn/SiO2 catalyst was addressed in the present study. The catalyst loading part was designed to be thicker than the inlet and outlet parts to reduce the rates of side reactions in the gas phase, and the optimal aspect ratio (L to D ratio) for no pressure drop and minimum side reactions was determined in experimental studies. Experiments were also conducted under a variety of operating conditions such as gas hourly space velocity (GHSV), CH4/O2 ratio and reaction temperature, and partial least-squares model was applied to predict the performance of the reactor. The validity of the developed model was corroborated by the comparison with experimental data, and normalized parametric sensitivity analysis was carried out. Finally, the genetic algorithm (GA) was applied to determine the optimal conditions for maximum production of ethane and ethylene.