Enhanced production of thermostable β-amylase and pullulanase in the presence of surfactants by Clostridium thermosulfurogenes SV2

The addition of the surfactants Triton X-100, CHAPS, Tween-80 and sodium taurocholate to Clostridium thermosulfurogenes SV2 culture individually resulted in a marked increase in the yields of thermostable beta-amylase and pullulanase. The stimulation of enzymes production was greater when the surfactants were added after 18 h of incubation of the culture. Upon treatment with 1.0 mM Triton X-100, 0.1 mM CHAPS, 0.1 mM Tween-80 and 0.1 mM sodium taurocholate, C. thermosulfurogenes SV2 produced 140, 34, 88 and 28% more beta-amylase and 114, 146, 47 and 28% more pullulanase than the control (lacking surfactants), respectively. Besides stimulation, the surfactants caused an increased secretion of the enzymes into the extracellular fluid. These surfactants also further enhanced the stability of the enzymes. All the surfactants tested were found to have a little inhibitory effect on the growth of the bacterium. (C) 1999 Elsevier Science Ltd. All rights reserved.