Statistical optimization of thermo-alkali stable xylanase production from Bacillus tequilensis strain ARMATI

Background: Xylanase from bacteria finds use in prebleaching process and bioconversion of lignocelluloses into feedstocks. The xylanolytic enzyme brings about the hydrolysis of complex biomolecules into simple monomer units. This study aims to optimize the cellulase-free xylanase production and cell biomass of Bacillus tequilensis strain ARMATI using response surface methodology (RSM). Results: Statistical screening ofmediumconstituents and the physical factors affecting xylanase and biomass yield of the isolate were optimized by RSM using central composite design at N = 30, namely 30 experimental runs with 4 independent variables. The central composite design showed 3.7 fold and 1.5 fold increased xylanase production and biomass yield of the isolate respectively compared to \u2018one factor at a time approach\u2019, in the presence of the basal medium containing birchwood xylan (1.5% w/v) and yeast extract (1% w/v), incubated at 40\ub0C for 24 h. Analysis of variance (ANOVA) revealed high coefficient of determination (R2) of 0.9978 and 0.9906 for the respective responses at significant level (p < 0.05). The crude xylanase obtained from the isolate showed stability at high temperature (60\ub0C) and alkaline condition (pH 9) up to 4 h of incubation. Conclusions: The cellulase-free xylanase showed an alkali-tolerant and thermo-stable property with potentially applicable nature at industrial scale. This statistical approach established a major contribution in enzyme production from the isolate by optimizing independent factors and represents a first reference on the enhanced production of thermo-alkali stable cellulase-free xylanase from B. tequilensis

Lignocellulosic biomass as potent feedstock resource for bioethanol production: Recent updates

Non-renewable fossil fuels are unable to fulfil today`s requirements of the societies in terms of energy requirements. The increasing demands for energy have emphasized the researchers to search for alternative sources of energy. Among distinct alternative energy resources, bioethanol has attracted an immense attention worldwide. Currently, lignocellulosic biomasses are considered as the largest renewable resources for the production of bioethanol due to its maximum abundance on the earth. Pre-treated lignocellulosic biomasses are converted into bioethanol by both direct microbial conversion and hydrolysis process along with fermentation. Immobilization and nanotechnology have shown effective roles in the improvement of bioethanol from lignocellulosic biomasses. This review focuses on recent developments in bioethanol production from varied lignocellulosic biomasses as cheep feedstock

Chemical composition, antioxidant activity and antibacterial mechanism of action from Marsilea minuta leaf hexane: methanol extract

Abstract Background In the present study, hexane: methanol (50:50) leaf extract of Marisela minuta has been evaluated for its chemical composition, antioxidant effect and the antimicrobial mechanism of action against food borne pathogenic bacteria. Results The phytochemical evaluation of extract by GC/MS revealed the major abundance of benzoic acid-4-ethoxyethyl ester (43.39%) and farnesol acetate (18.42%). The extract exhibited potential antioxidant and free radical scavenging properties with promising antibacterial activities against the test pathogens with Pseudomonas aeruginosa being the most susceptible with maximum inhibition zone (17 mm) and IC50 value of 125 µg, respectively. The significant (p < 0.05) increase in intracellular super oxide dismutase (SOD), protein leakage, extracellular alkaline phosphatase and lactate dehydrogenase in treated test pathogens suggested an increase in oxidative stress reveling the mechanism of action of phytochemicals. Scanning electron microscopy analysis of treated pathogens also showed swollen and distorted cells. The bioactive molecules in the extract were efficiently docked with virulent enzymes and farnesol acetate showed best energy value of − 5.19 and − 4.27 kcal/mol towards Topoisomerase IV and SHV-2 respectively. Benzoic acid-4-ethoxyethyl ester showed best binding against TEM-72 with low binding energy value of − 4.35 kcal/mol. Conclusion Due to its antioxidant and antibacterial properties, the leaf extract of M. minuta may act as promising natural additives to prevent food spoilage bacteria

Optimization of Thermo-Alkali Stable Amylase Production and Biomass Yield from Bacillus sp. Under Submerged Cultivation

The present context was investigated to optimize amylase production and cell biomass of poultry-associated Bacillus sp. using a conventional as well as statistical approach. Box-Behnken design (BBD) matrix at N = 29 was employed to optimize four independent variables, selected from one factor at a time (OFAT) technique, for maximum amylase production and biomass yield. The relative activity of crude amylase obtained from the isolate showed stability at high temperature (60 °C) and alkaline condition (pH 9) up to 4 h of incubation, thereby indicating its alkali-tolerant and thermo-stable property. The BBD resulted in enhanced amylase activity of 145.32 U/mL when the basal medium was slightly acidic (pH 6) and kept at a temperature of 35 °C with the shaking speed of 130 rpm, in addition to being incubated for 24 h. The selected factors, when employed with this statistical optimization approach, showed 1.5-fold and 2-fold enhancements in the amylase production and biomass yield respectively compared to the OFAT method. Analysis of variance (ANOVA) revealed high coefficient of determination (R2) of 0.96 to 0.99 for both the responses at significant level (p &lt; 0.05). Three-dimensional response and 2D contour plot of the quadratic model showed interdependent interaction between the effective variables. Long-term thermo-alkali stability of amylase obtained from Bacillus sp. suggested not only its wide applications in pharmaceutical, food and biotechnological industries, but also suggested a potent replacement of existing amylases on the market

Anti-inflammatory activity of rhein isolated from the flowers of Cassia fistula L. and possible underlying mechanisms

Objective: Anti-inflammatory activity of rhein in animal models with potential mechanism of actions. Methods: Rhein was isolated from Cassia fistula L. flowers collected in Chennai, Tamil Nadu, India. Its anti-inflammatory activity was then investigated in Wistar rats and mice using carrageenan-induced hind paw oedema, croton oil-induced ear oedema, cotton pellet-induced granuloma and acetic acid-induced vascular permeability models. Results: Administration of rhein (10, 20, 40 mg/kg) significantly (p < 0.05) inhibited carrageenan-induced paw oedema in rats and croton oil-induced ear oedema in mice in dose-dependent manners. Continual administration of rhein to rats using implanted cotton pellets significantly (p < 0.05) reduced granuloma formation (20 mg/kg: 17.24%; 40 mg/kg: 36.12%) compared to control group animals. Administration of rhein increased the activities of catalase (CAT), superoxide dismutase (SOD) and glutathione peroxidase (GSH-px) and decreased the levels of nitrite, interleukin-6 (IL-6), interleukin-1β (IL-1β), tumor necrosis factor-α (TNF-α), malondialdehyde (MDA) and vascular endothelial growth factor (VEGF) compared to control animals. Western blotting results revealed that rhein diminished carrageenan-induced cyclooxygenase (COX)-2 and inducible nitric oxide synthase (iNOS) and increased heme oxygenase (HO)-1, nuclear factor erythroid 2–related factor 2 (Nrf2), peroxisome proliferator-activated receptor gamma (PPAR)-γ and heat shock protein (HSP)-72 expression after 6 h in the paw oedema model. Conclusion: The anti-inflammatory mechanisms of rhein might be related to decrease in the levels of MDA, iNOS and COX-2 and the stimulation of HO-1, PPAR-γ and Nrf2 expression via increases in the activities of CAT, SOD and GSH-px through the suppression of nitrite, TNF-α, IL-6 and IL-1β. Keywords: Anti-inflammatory, Rats, Paw oedema, Ear oedema, Cassia fistula, Rhei

Isolation and characterization of Aspergillus sp. for the production of extracellular polysaccharides by response surface methodology

In this study, Aspergillus sp. was isolated for the production of extracellular polysaccharide. The process parameters were initially optimized by traditional methods. The cheap substrate, wheat bran was used for the production of extracellular polysaccharide in solid state fermentation. Supplementation of (1%, w/w) maltose, gelatin enhanced EPS production (5.36 mg/g). The salts such as, Cu2+ (4.9 mg/g), Ca2+ (3.5 mg/g), Zn2+ (2.9 mg/g), Mn2+ (3.4 mg/g) and Mg2+ (1.8 mg/g) stimulated EPS production. In two level full factorial experimental designs, the EPS yield varied from 3.18 to 11.65 mg/g wheat bran substrate with various combinations of the components supplemented with wheat bran substrate. Among these selected factors in central composite design, maltose significantly influenced on extracellular polysaccharide production. Keywords: Apergillus sp., Extracellular polysaccharide, Response surface methodolog