NISCAIR Online Periodicals Repository Community: IJBT Vol.11 [2012]

Hydrolysis of lignocellulosic feed stock by Ruminococcus albus in production of biofuel ethanol

Title: Hydrolysis of lignocellulosic feed stock by Ruminococcus albus in production of biofuel ethanol

Authors: Mutalik, Sampana; Kumar, C S Vinod; Swamy, Subramanya; Manjappa, S

Abstract: Ethanol is an alternative to fossil fuel. Current ethanol production processes using crops, such as, sugarcane and corn are well-established. However, utilization of a cheaper substrate, such as, lignocellulose makes bioethanol more purposeful. Biologically mediated processes are promising for energy conversion, in particular, for the conversion of lignocellulosic biomass into fuels. In the present study, optimized cellulosic ethanol production from bagasse and sorghum using Ruminococcus albus isolated from rumen of herbivores animals was attempted. R. albus could depolymerise cellulose and hemicellulose as well as could tolerate stress conditions (variable substrate concentration, pH, and temperature). Optimum temperature, pH and substrate concentration for hydrolyses of both bagasse and sorghum by R. albus were found to be 39°C, 8.8 and 3.5%, respectively. For the feed stock (3.5%) of bagasse and sorghum, ethanol yield of 19.8 g/L and 17.42 g/L, respectively was obtained.

Page(s): 453-457

Isolation of a halophilic Virgibacillus sp. EMB13: Characterization of its protease for detergent application

Title: Isolation of a halophilic Virgibacillus sp. EMB13: Characterization of its protease for detergent application

Authors: Sinha, Rajeshwari; Khare, S K

Abstract: Isolation and characterization of a moderately halophilic bacterium, Virgibacillus sp. EMB13, from the West coast of India has been described in the present study. It produced five different extracellular proteases. Conditions were optimized for maximum protease production. Under optimized conditions, viz., a medium containing (%, w/v) yeast extract, 1.0; peptone, 0.5; mannitol, 0.5; NaCl, 0.5; KCl, 1.0; CaCl₂, 0.03 and MgSO₄, 0.04 with pH 8, it produced 270 U protease mL^-1. The protease was partially purified by DEAE ion exchange and Sephadex G-75 gel filtration chromatography. The purified preparation contained two unseparated proteases with apparent molecular masses of 49 and 54 kDa, respectively. The preparation was stable at different concentrations of NaCl (0-15%, w/v) and pH range 6.0-12.0. It exhibited maximal activity at pH 7.5, temperature 50°C and 1% (w/v) NaCl. The K_m and V_max values towards casein were 7.5 mg mL^-1 and 156.25 µg min^-1 mL^-1, respectively. Inhibition of their proteolytic activity by EDTA and 1,10-phenanthroline indicated them to be metalloprotease in nature. The proteases exhibited remarkable stability in the presence of salt and organic solvents. These properties enable them for novel applications in non-aqueous enzymology and as an additive in detergent formulations.

Page(s): 416-426

Chromosomal location of non-hypersensitive leaf rust resistance genes in bread wheat cultivar PBW65 using microsatellite markers

Title: Chromosomal location of non-hypersensitive leaf rust resistance genes in bread wheat cultivar PBW65 using microsatellite markers

Authors: Khan, M A; Kamaluddin; Saini, R G

Abstract: Microsatellite or simple sequence repeat (SSRs) markers have been powerful tool for genetic mapping in wheat. Indian bread wheat (Triticum aestivum L.) cultivar PBW65 has shown significant level of resistance to most virulent race 77-5 of leaf rust (Puccinia triticina). It has been indicated that PBW65 expresses non-hypersensitive type of resistance against race 77-5. F₂ and F₃ crossing of PBW65 with WL711, a leaf rust susceptible wheat cultivar, and allelic tests with such already known genes (present in cultivars RL 6058 and HD 2009) revealed that cultivar PBW65 could be a potential source of novel non-hypersensitive leaf rust resistance genes. So far, only non-hypersensitive leaf rust resistance gene Lr34 was found to be effective under Indian conditions. Attempts to locate such durable leaf rust resistance genes in PBW65 through microsatellite markers showed 2B, 2D and 3D as critical chromosomes for PBW65. The primer Xgwm341 (3D) was found located 41.5 cM away from gene LrPBW1 in PBW65.

Page(s): 412-415

Remediation of synthetic dyes from wastewater using yeast—An overview

Title: Remediation of synthetic dyes from wastewater using yeast—An overview

Authors: Das, Nilanjana; Charumathi, D

Abstract: Synthetic dyes released by various industries pose a real concern to the environmental safety. Existing physico-chemical methods of dye removal from effluents suffer from severe constraints like low efficiency, high operational cost and large amount of sludge generation. Over the last two decades, considerable work has been done with the goal of using microorganisms as bioremediation agents in the treatment of dye containing wastewaters. Microorganisms are capable of removing dyes due to their high metabolic potential. Compared to bacteria and filamentous fungi, yeasts exhibit attractive features. In recent years, there has been intensive research on dye removal by yeast species. It is becoming a promising alternative to replace or supplement existing treatment processes. The present article provides a selective overview of past achievements and present scenario of using yeast for the removal of synthetic dyes from water environment. Updated information on the mechanism of dye removal by various yeast genera via processes like biosorption, bioaccumulation and biodegradation are discussed.

Page(s): 369-380