Anil Kumar Patel

Role and significance of beta-glucosidases in the hydrolysis of cellulose for bioethanol production.

One of the major challenges in the bioconversion of lignocellulosic biomass into liquid biofuels includes the search for a glucose tolerant beta-gulucosidase. Beta-glucosidase is the key enzyme component present in cellulase and completes the final step during cellulose hydrolysis by converting the cellobiose to glucose. This reaction is always under control as it gets inhibited by its product glucose. It is a major bottleneck in the efficient biomass conversion by cellulase. To circumvent this problem several strategies have been adopted which we have discussed in the article along with its production strategies and general properties. It plays a very significant role in bioethanol production from biomass through enzymatic route. Hence several amendments took place in the commercial preparation of cellulase for biomass hydrolysis, which contains higher and improved beta-glucosidase for efficient biomass conversion. This article presents beta-glucosidase as the key component for bioethanol from biomass through enzymatic route.

Alpha amylase from a fungal culture grown on oil cakes and its properties

Fermentacao no Estado Solido foi empregada na producao de alfa-amilase usando Aspergillus niger. Diferentes tipos de torta foram utilizadas, como torta de oleo de coco (COC), torta de de oleo de amendoim (GOC) torta de oleo de sesamo (SOC), torta de palma (PKC) e torta de oleo de oliva (OOC) foram selecionadas para serem usadas como substratos para producao de enzima e comparadas com o farelo de trigo (WB), GOC foi escolhido por ser o que produziu maiores concentracoes de enzima. A combinacao WB e GOC (1:1) resultou em maiores titulos da enzima quando em comparacao com os substratos individuais. A maxima concentracao de enzima (9196 U/ gms) foi obtida quando a FES foi conduzida utilizando WB + GOC, com umidade de 64% e suplementada com lactose e nitrato de amonia (1% cada) a 300C por 72 horas utilizando 2 mL de uma suspensao de esporo (6x107sporos/ml). A purificacao parcial da enzima usando fracoes de sulfato de amonio resultou num aumento de 2-4 vezes o aumento da atividade. A enzima apresentou um peso molecular de 68 Kda pelo SDS_PAGE. Exceto Mn, todos os outros ions metalicos como Ca, K, Na, Mg sao inibitorios na producao da enzima.

Probiotic Bile Salt Hydrolase: Current Developments and Perspectives

Probiotic has modernized the current dietetic sense with novel therapeutic and nutritional benefits to the consumers. The presence of bile salt hydrolase (BSH) in probiotics renders them more tolerant to bile salts, which also helps to reduce the blood cholesterol level of the host. This review focuses on the occurrence of bile salt hydrolase among probiotics and its characterization, importance, applications, and genetics involved with recent updates. Research on bile salt hydrolase is still in its infancy. The current perspective reveals a huge market potential of probiotics with bile salt hydrolase. Intensive research in this field is desired to resolve some of the lacunae.

Biological upgrading of volatile fatty acids, key intermediates for the valorization of biowaste through dark anaerobic fermentation.

VFAs can be obtained from lignocellulosic agro-industrial wastes, sludge, and various biodegradable organic wastes as key intermediates through dark fermentation processes and synthesized through chemical route also. They are building blocks of several organic compounds viz. alcohol, aldehyde, ketones, esters and olefins. These can serve as alternate carbon source for microbial biolipid, biohydrogen, microbial fuel cells productions, methanisation, and for denitrification. Organic wastes are the substrate for VFA platform that is of zero or even negative cost, giving VFA as intermediate product but their separation from the fermentation broth is still a challenge; however, several separation technologies have been developed, membrane separation being the most suitable one. These aspects will be reviewed and results obtained during anaerobic treatment of slaughterhouse wastes with further utilisation of volatile fatty acids for yeast cultivation have been discussed.

Production, purification and chemical characterization of the catecholate siderophore from potent probiotic strains of Bacillus spp.

The aim of the present study was to characterize the probiotic qualities of Bacillus isolates and study their siderophore prior to possible siderophoregenic probiotic application for iron nutrition in animals and humans. Bacillus strains were selectively isolated from dairy waste and mango pulp waste. Best two siderophore positive isolates, JHT3 and DET6 showed high homology with Bacillus megaterium (98%) and B. subtilis (99%), respectively, using partial 16S-rRNA sequencing and biochemical characterization. These isolates produced catecholate type of siderophore under iron stressed conditions and were screened for probiotic properties as per WHO and FAO guidelines. Spores of these strains showed excellent tolerance in partially simulated gastrointestinal tract conditions and exhibited antimicrobial activity against organisms such as Staphylococcus aureus, Micrococcus flavus and Escherichia coli. Importantly, these isolates were susceptible to the most of the antibiotics tested, in conflict that they would not donate resistance determinants if administered in the form of probiotic preparations.

Separation and fractionation of exopolysaccharides from Porphyridium cruentum

In this work the extraction of EPSs from culture media of Porphyridium cruentum, by dialysis, solvent-precipitation with 3 polar alcohols (methanol, ethanol and isopropanol) and membrane separation techniques has been studied. Diafiltration (DF) using a membrane with a 300 kDa molecular weight cut off was the most efficient technique compared to solvent-extraction and dialysis methods. After extraction, EPS fraction was characterized in terms of rheological properties and biochemical content. The product exhibited shear thinning behavior and a critical overlap concentration equal to 0.6 g/L. The monosaccharide composition was investigated after acidic hydrolysis. Xylose, galactose, glucose and glucuronic acid were identified as the main constitutive monomers.

Enhanced cellulase production by Penicillium oxalicum for bio-ethanol application

Present study was focused on cellulase production from an indigenously isolated filamentous fungal strain, identified as Penicillium oxalicum. Initially, cellulase production under submerged fermentation in shake flasks resulted in cellulase activity of 0.7 FPU/mL. Optimization of process parameters enhanced cellulase production by 1.7-fold and resulted in maximum cellulase activity of 1.2 FPU/mL in 8 days. Cellulase production was successfully scaled-up to 7 L fermenter under controlled conditions and incubation time was reduced from 8 days to 4 days for achieving similar cellulase titer. Optimum pH and temperature for activity of the crude enzyme were pH 5 and 50 °C, respectively. At 50 °C the produced cellulase retained approximately 50% and 26% of its activity at 48 h and 72 h, respectively. Hydrolytic efficiency of P. oxalicum was comparable to commercial cellulase preparations which indicate its great potential for application in the lignocellulose hydrolysis.

Biohydrogen production from a novel alkalophilic isolate Clostridium sp. IODB-O3

Hydrogen producing bacteria IODB-O3 was isolated from sludge and identified as Clostridium sp. by 16S rDNA gene analysis. In this study, biohydrogen production process was developed using low-cost agro-waste. Maximum H2 was produced at 37°C and pH 8.5. Maximum H2 yield was obtained 2.54±0.2mol-H2/mol-reducing sugar from wheat straw pre-hydrolysate (WSPH) and 2.61±0.1mol-H2/mol-reducing sugar from pre-treated wheat straw enzymatic-hydrolysate (WSEH). The cumulative H2 production (ml/L), 3680±105 and 3270±100, H2 production rate (ml/L/h), 153±5 and 136±5, and specific H2 production (ml/g/h), 511±5 and 681±10 with WSPH and WSEH were obtained, respectively. Biomass pre-treatment via steam-explosion generates ample amount of WSPH which remains unutilized for bioethanol production due to non-availability of efficient C5-fermenting microorganisms. This study shows that Clostridium sp. IODB-O3 is capable of utilizing WSPH efficiently for biohydrogen production. This would lead to reduced economic constrain on the overall cellulosic ethanol process and also establish a sustainable biohydrogen production process.

Biofuels from Biomass

Biofuels are the only hope to decrease the dependency on fossil fuel so as to have carbon footprints for a healthier and more eco-friendly future. Technologies for various alternative fuels are sustainable needs to mature fast so as to replace petroleum-based fuels. Bioethanol production from lignocellulosic biomass would be unavoidable if liquid fossil fuels are to be replaced by renewable and sustainable alternatives, as it is ubiquitous in nature accounting for 50 % of all the biomass available in the world. Conversion of lignocellulosic biomass to fuel ethanol involves various process stages, and each stage contributes to the overall economy of the process. The utilization of lignocellulosic biomass for ethanol production for transportation sector necessitates the large-scale production technology to be cost-effective and environmentally sustainable. Biological conversion of lignocellulosics to fermentable sugars, employing hydrolyzing enzymes, is at present the most attractive alternative due to environmental concerns, though there are several hindrances on the way of developing economically feasible technology due to the presence of lignin. The present chapter discusses the various alternative fuels to petroleum-based fuels, Indian biofuel policy, status of biofuels specially bioethanol globally as well as in India and suitability of lignocellulosic biomass for bioethanol production and various technical steps which add major part of the cost to the overall process.

Industrial Enzymes: Xylanases

Xylanases are inevitable hydrolytic enzymes required in plant cell wall hydrolysis. Various forms of xylanases exist in nature, which belong to the glycoside hydrolase families, namely families 5, 7, 8, 10, 11, and 43. The sources of xylanases vary, ranging from prokaryotes to eukaryotes. Depending upon the nature of the xylanase, they are used in specific industries. Various optimization techniques and statistical approaches are used for the controlled production of xylanases. Optimized conditions have been adopted in various industries for the production and improved activity of these enzymes. Recombinant DNA technology has been well adopted for the genetic and mutational improvement of the microorganisms not only to improve the enzyme titers but also in developing desirable properties for their application using the techniques of cloning and overexpression. Xylanases find numerous industrial applications, including in the paper and pulp industries, food and feed industries, biofuel industry, waste management, etc.