%0 Journal Article
%T Optimization of Fermentation Medium for the Production of Glucose Isomerase Using Streptomyces sp. SB-P1
%A Sheetal Bhasin
%A H. A. Modi
%J Biotechnology Research International
%D 2012
%I Hindawi Publishing Corporation
%R 10.1155/2012/874152
%X The combination of medium ingredients has a profound influence on the metabolic pathways running in the microorganism which regulates the production of numerous metabolites. Glucose isomerase (GI), an enzyme with huge potential in the market, can isomerise glucose into fructose. GI is used widely for the production of High-Fructose Corn Syrup (HFCS). HFCS is used as a sweetener in food and pharmaceutical industries. Streptomyces are well-known producers of numerous enzymes including glucose isomerase. An array of 75 isolates was screened for the production of glucose isomerase. The isolate Streptomyces sp. SB-P1 was found to produce maximum amount of extracellular GI. Sucrose and raffinose among pure carbon sources and corn cob and wheat husk among crude agro residues were found to yield high enzyme titers. Potassium nitrate among pure nitrogen sources and soy residues among crude sources gave maximum production. Quantitative effect of carbon, nitrogen, and inducer on GI was also determined. Plackett-Burman design was used to study the effect of different medium ingredients. Sucrose and xylose as carbon sources and peptone and soy residues as nitrogen sources proved to be beneficial for GI production. 1. Introduction GI (EC 5.3.1.5) catalyses the conversion of glucose into fructose. The most important application of GI is the production of High-Fructose Corn Syrup (HFCS). It is an equilibrium mixture of fructose and glucose. Fructose, also known as fruit sugar, is the sweetest natural sugar and is found in fruits, vegetables and honey. HFCS has wide applications in pharmaceutical and food industries. It is added in medicated syrups, beverages, baking, canning and confectionary items as a sweetening agent [1]. Ge et al. [2] developed a process for continuous production of HFCS by Immobilised Glucose Isomerase (IGI). GIs characterized from different microbial sources vary in molecular mass from 80 to 195£¿kDa and are composed of two or four identical subunits. Glucose isomerase from Streptomyces is a tetramer composed of four identical polypeptide chains of 43,000 daltons each [1, 3]. Marshall and Kooi in 1957 [4] for the first time reported the production of glucose isomerase from Pseudomonas hydrophila. Since then many mesophilic, thermophilic, a few psychrophilic, aerobic, and anaerobic organisms have been reported to produce GI. Streptomycetes have been the organisms of choice for GI production by numerous researchers. The thrust areas to work upon for medium formulation are independence of xylose and cobalt ions. Xylose works as an inducer for GI in
%U http://www.hindawi.com/journals/btri/2012/874152/