Effects of surfactants tween 80 and rhamnolipid on the extracellular enzymes amylase, protease, CMCase and xylanase of one strain

The chemical surfactant Tween 80 and biosurfactant rhamnolipid were added to the solid-state fermentation processes of a strain of actinomycete Streptomyces badius. The extracellular amylase, protease, carboxymethyl cellulose enzyme (CMCase) and xylanase were analyzed during the fermentation process. In addition, the pH of the fermentation substrate, microbial population and the degradation of the organic matter were determined. The results showed that Tween 80 increased the activities of amylase, protease, CMCase and xylanase to different extents while rhamnolipid only had an obvious stimulatory effect on xylanase. Neither Tween 80 nor rhamnolipid had an obvious effect on the pH of the fermentation substrate. As a result of the improved enzyme activities, the degradation rates of organic matter of the treatments with surfactants were higher than that of the control. The results indicated that Tween 80 is a common stimulant for most enzymes, while rhamnolipid can only act with some specific enzyme, such as xylanase.