Influence of various fermentation variables on exo-glucanase production in Cellulomonas flavigena

Abstract

The influence of carbon and nitrogen sources on the production of exo-glucanase was investigated. The enzyme production was variable according to the carbon or nitrogen source used. Levels of β-cellobiohydrolase (CBH) were minimal in the presence of even low concentrations of glucose. Enzyme production was stimulated by other carbohydrates and thus is subject to carbon source control by easily metabolizable sugars. In Dubos medium, on cellobiose, the cellobiohydrolase titres were 2-to 110-fold higher with cells growing on monomeric sugars and 2.7 times higher than cells growing on other disaccharides. aCellulose was the most effective inducer of β-cellobiohydrlase and filter paperase (FPase) activities, followed by kallar grass straw. Exogenously supplied glucose inhibited the synthesis of the enzyme in cultures of Cellulomonas flavigena. Nitrates were the best nitrogen sources and supported greater cell mass, cellobiohydrolase and FPase production. During growth on α-cellulose containing 8-fold sodium nitrate concentration, maximum volumetric productivities (Q p ) of β-cellobiohydrolase and FPase were 87.5 and 79.5 IU/l

Optimization of fermentation conditions for cellulase production by Bacillus subtilis CY5 and Bacillus circulans TP3 isolated from fish gut

“…Coral et al (2002) reported the optimum temperature for CMCase activity as 40ºC in Aspergillus niger Z10 strain. Rajoka et al (1998) and Rajoka (2004), however, observed suppressed exoglucanase production at temperatures higher than 30ºC in Cellulomonas biazotea and C. flavigens, respectively. At lower temperature, substrate transport across the cells is suppressed and lower product yields are attained.…”

“…On the contrary, Spiridonov and Wilson (1998) found that NH 4 compounds are the most favourable nitrogen sources for protein and cellulase synthesis. Rajoka (2004) reported KNO 3 and NH 4 NO 3 as the best nitrogen sources for cellulase synthesis in C. flavigena.…”

“…(Garcia-Martinez et al 1980, Prasetsan andDoelle 1987). Rajoka (2004), however, reported pH 7.3 as optimum for production of β-cellobiohydrolase (CBH) in Cellulomonas flavigens. Like pH, temperature is one of the most important parameters essential for the success of a fermentation reaction.…”

“…An elaborate investigation is therefore, required to establish the optimum conditions to scale up enzyme production in an individual fermentation process. Although there are reports on the influence of various fermentation variables on cellulase production by different bacteria and fungi isolated from various natural environments (GarciaMartinez et al 1980, Stewart and Parry 1981, Coral et al 2002, Rajoka 2004, Immanuel et al 2006, information on the optimum fermentation conditions for cellulase production by fish gut bacteria is lacking. In the present investigation, the environmental and nutritional parameters for fermentation were optimized to enhance cellulase production by the bacterial strains B. subtilis CY5 and B. circulans TP3, isolated from the gut of common carp, Cyprinus carpio L., and Mozambique tilapia, Oreochromis mossambicus (Peters, 1852), respectively.…”

Optimizing Cellulase Production from Municipal Solid Waste (MSW) using Solid State Fermentation (SSF)

“…Cellulase can be produced by various bacteria such as Bacillus subtilus, Bacillus circulans [4] (Bacillus sphaericus-JS1 [5], Cellulomonas flavigena [6] and fungi like Aspergillus sp. [7] and Trichoderma reesei [8].…”