Sana Zahoor

Bio: Sana Zahoor is an academic researcher from Virtual University of Pakistan. The author has contributed to research in topics: Medicine & Fermentation. The author has an hindex of 6, co-authored 13 publications receiving 119 citations.

Wheat bran as a brown gold: Nutritious value and its biotechnological applications

Abstract: Wheat bran, a by-product of wheat milling industry, is the outermost covering of wheat grain. It has relatively diverse application in food, feed, medicine and fermentation industries due to its richness in carbohydrates (mostly fibers), protein and fats which makes it an important dietary element. Its importance from medical view point is well documented especially in reducing blood plasma cholesterol and prevention of cardiovascular diseases and certain cancers, that is, colon cancer. In fermentation industry, wheat bran can be used as a substrate for production of a range of products such as biomass, enzyme, biofuel and production of other metabolites. In short wheat bran has immense applications and market value which makes it so important to be considered as brown gold. Key words: Wheat bran, enzyme production, biofuel, food, health.

Cloning and expression of β-glucosidase gene from Bacillus licheniformis into E. coli BL 21 (DE3)

Abstract: A 1.4 Kb fragment of Bacillus licheniformis ATCC 14580 encoding β-glucosidase was cloned and expressed in Escherichia coli. β-Glucosidase expressed by E. coli harboring cloned gene was located entirely in the intracellular fraction. Recombinant β-glucosidase protein was purified to homogeneity level and the molecular weight was found to be 53 kDa using sodium dodecyl sulfate polyacrylamide gel electrophoresis analysis. It gave maximum activity at 50°C and pH 6. K m and V max were 0.206 mM and 1.26 U/mg, respectively, with p-nitrophenyl-β-D-glucopyranoside, while activation energy Ea, enthalpy of activation ?H and entropy of activation ΔS were found to be 66.31 kJ/mol, 64.04 kJ/mol and 48.28 J/mol/K, respectively. The pKa1 and pKa2 of the ionizable groups of active site residues involved in Vmax were found to be 5.5 and 7.0, respectively. When the recombinant β-glucosidase protein was used as a member of consortium with endoglucanase and exoglucanase for the saccharification of wheat straw, 123% increase in saccharification was observed.

Kinetics and Thermodynamic Study of Urease Extracted from Soybeans

Abstract: The present study is concerned with the kinetics and thermodynamic study of urease extracted from soybeans. The effect of pH, temperature, concentration of substrate and incubation time on the urease activity was examined. Maximum urease activity (86.79 ± 2.43 U/g) was obtained at 30 o C and pH 8.0 after 60 sec of incubation. Kinetics constants i.e. Km and Vmax were estimated by using Lineweaver-Burk plot and were found to be 36.49 mM and 87.72 U/g, respectively. Thermodynamic constants i.e. Activation energy (Ea), change in enthalpy (ΔH) and change in entropy (ΔS) were calculated using Arrhenius plot and were found to be 5.7 KJ/mol, 3.468 KJ/mol and -4.57 KJ/mol respectively.

Characterization Of A Novel Hydrolytic Enzyme Producing Thermophilic Bacterium Isolated From The Hot Spring Of Azad Kashmir-Pakistan

Abstract: A thermophilic bacterium (TP-2) was isolated from the Tatta Pani hot spring in Azad Kashmir and was characterized using phenotypic and genotypic characters. The strain developed cream colored, round, smooth, flat and slimy colonies while the cells were Gram positive rods that ranged in size from about 2.1-3.6 μm to 0.2-0.3 μm in width. Sequence analysis of its 16S rRNA gene showed that isolate TP-2 had 89% homology with Geobacillus debilis. It grew within pH range of 5.5 to 8.5 with optimum growth at pH 7.0. The isolate showed optimum growth at 65oC and gave positive results for gelatin hydrolysis (GEL), ortho nitrophenyl-β-D-galactopyranosidase (ONPG), and nitrate production and produced acid from sucrose, glucose and maltose. It utilized glucose, fructose, maltose, lactose, sucrose, xylan, starch, filter paper and carboxymethylcellulose as sole carbon source. Isolate TP-2 produced significant amount of industrially important enzymes i.e. extracellular α-amylase, CMCase, FPase, Xylanase, Protease and Lipase and intracellular CMCase and FPase.

Microbial fuel cells as an alternative energy source: current status

Abstract: Microbial fuel cell (MFC) technology is an emerging area for alternative renewable energy generation and it offers additional opportunities for environmental bioremediation. Recent scientific studies have focused on MFC reactor design as well as reactor operations to increase energy output. The advancement in alternative MFC models and their performance in recent years reflect the interests of scientific community to exploit this technology for wider practical applications and environmental benefit. This is reflected in the diversity of the substrates available for use in MFCs at an economically viable level. This review provides an overview of the commonly used MFC designs and materials along with the basic operating parameters that have been developed in recent years. Still, many limitations and challenges exist for MFC development that needs to be further addressed to make them economically feasible for general use. These include continued improvements in fuel cell design and efficiency as well scale-up with economically practical applications tailored to local needs.

Composition and functionality of wheat bran and its application in some cereal food products

Abstract: Summary Production of wheat bran (WB) for human consumption is estimated to be about 90 million tonnes per year. WB is a cheap and abundant source of dietary fibre which has been linked to improved bowel health and possible prevention of some diseases such as colon cancer. It also contains minerals, vitamins and bioactive compounds such as phenolic acids, arabinoxylans, alkylresorcinol and phytosterols. These compounds have been suggested as an aid in prevention of noncommunicable diseases such as cardiovascular disease. This article discusses WB extraction, its nutritional properties, potential health benefits, effects on quality and sensory properties of some cereal foods, and its application in some baked products as well as in fried cereal snacks, as an additive for oil reduction and fibre enrichment.

Catalytic properties, functional attributes and industrial applications of β-glucosidases

Abstract: β-Glucosidases are diverse group of enzymes with great functional importance to biological systems. These are grouped in multiple glycoside hydrolase families based on their catalytic and sequence characteristics. Most studies carried out on β-glucosidases are focused on their industrial applications rather than their endogenous function in the target organisms. β-Glucosidases performed many functions in bacteria as they are components of large complexes called cellulosomes and are responsible for the hydrolysis of short chain oligosaccharides and cellobiose. In plants, β-glucosidases are involved in processes like formation of required intermediates for cell wall lignification, degradation of endosperm's cell wall during germination and in plant defense against biotic stresses. Mammalian β-glucosidases are thought to play roles in metabolism of glycolipids and dietary glucosides, and signaling functions. These enzymes have diverse biotechnological applications in food, surfactant, biofuel, and agricultural industries. The search for novel and improved β-glucosidase is still continued to fulfills demand of an industrially suitable enzyme. In this review, a comprehensive overview on detailed functional roles of β-glucosidases in different organisms, their industrial applications, and recent cloning and expression studies with biochemical characterization of such enzymes is presented for the better understanding and efficient use of diverse β-glucosidases.

Production of cellulolytic enzymes from ascomycetes: comparison of solid state and submerged fermentation

Abstract: Optimizing production of cellulose degrading enzymes is of great interest in order to increase the feasibility of constructing biorefinery facilities for a sustainable supply of energy and chemical products. The ascomycete phylum has a large potential for the production of cellulolytic enzymes. Although numerous enzymatic profiles have already been unraveled, the research has been covering only a limited number of species and genera, thus leaving many ascomycetes to be analyzed. Such analysis requires choosing appropriate media and cultivation methods that ensure enzyme profiles with high specificities and activities. However, the choice of media, cultivation methods and enzyme assays highly affect the enzyme activity profile observed. This review provides an overview of enzymatic profiles for several ascomycetes covering phylogenetically distinct genera and species. The profiles of cellulose degrading enzymes are correlated to the use of submerged culturing and solid state culturing. Even though submerged fermentation (SmF) is the most common method for commercial enzyme production, the use of solid state fermentation (SSF) is praised as a promising way of producing higher enzyme titers compared to SmF. Current comparisons of enzyme activities obtained from SmF and SSF do not account for all variables thereby complicating comparisons and diminishing credibility of conclusions being made. This review aims at providing guidelines for directly comparing cellulolytic enzyme production in SSF with SmF to advance future research of enzyme production.

Wheat bran biorefinery--a detailed investigation on hydrothermal and enzymatic treatment.

Abstract: Due to the enormous quantities arising in the milling industry and its specific properties, wheat bran can be considered as a feedstock for future biorefineries. In the present work, a detailed investigation was carried out on the hydrothermal (140-200°C) and enzymatic treatment of wheat bran. After hydrothermal pretreatment and a subsequent enzymatic hydrolysis a glucose yield of 65% and 90% was achieved, respectively. Interestingly, the hemicelluloses could be disintegrated to monomers only to approx. 50%. About 70% of the proteins were dissolved, however, practically no free amino acids were obtained under given conditions. Severe treatment conditions induce elevated losses of some amino acids. Minerals could be extracted almost completely. To disintegrate fat into glycerol and fatty acids severe process conditions were necessary. The formation of undesired by-products such as furfural or hydroxymethylfurfural starts at approx. 180°C.