Production Of Extracellular Xylanase Research Articles

Extracellular production of xylanase L in Escherichia coli using excretion vector pEAP2.

Extracellular production of xylanase L in Escherichia coli using excretion vector pEAP2.

Studies on the extracellular xylanase activity of some thermophilic actinomycetes

An agar plate-clearing assay was used to screen 37 thermophilic actinomycete strains for extracellular xylanase production. The xylanase activity in culture supernatants of strains representing Saccharomonospora viridis and three Thermomonospora spp. was characterised by measurement of reducing sugar released from oat spelt xylan and analysis of degradation products by thin-layer chromatography. In all four species, xylanase activity was optimal within the temperature range 60–75°C and between pH 5 and pH 8. While culture supernatants of Thermomonospora strains incubated at 70°C for 60 min retained >80% of their activity, that of S. viridis was almost, totally inactivated.

Production of Extracellular Xylanase from Intestinal Bacteria in Termite

Although the involvement of intestinal bacteria in the degradation of lignocellulosic materials is poorly understood xylanolytic activity of termite has been studied extensively. The present study was designed to identify potential xylanolytic bacteria from termite intestine and the isolated bacterium was studied with a view to preparing low cost medium and optimizing the cultural conditions in Dubos liquid medium. The bacterium produced highest activity of the enzyme (0.86 U/ml) on birchwood xylan as carbon substrate. Wheat bran a relatively cheap lignocellulosic material was found as good inducer of the enzyme. When grown on 4% wheat bran in Dubos liquid medium with an initial pH 6.0 under shaking incubation at 200 rpm at 40°C for 24 h, the bacterium produced the maximum activity of the extracellular xylanase (1.5 U/ml). These results strongly indicated that the bacterium from the intestine in termite is able synthesize xylanase activity on various substrate and the enzyme production can be increased by optimizing the overall cultivation parameters. Keywords: Xylanase; Termite intestinal bacteriaDOI: http://dx.doi.org/10.3329/bjm.v25i2.4874 Bangladesh J Microbiol, Volume 25, Number 2, December 2008, pp 123-127