Microbial Degradation Of Larch Tannin To Catechin

Larch tannin, belonging to condensed tannin, has various biological activities, such as antioxidant, free radical scavenging, anticancer, senescence-resistant, etc. It has been proven that the chain length of condensed tannins has significant influence on their biological potential, and catechins are highly active in their antioxidative or other abilities.In this study, a predominant strain which could tolerate certain larch tannin concentration was isolated, a method was established to determine larch tannin fractions and the degradative products, and optimal conditions under which larch tannin was biodegraded to catechin were built up. The results indicated that paper chromatometry could be applied to separate different fractions of larch tannin, and vanillin-HCl measurement together with UV spectrophotometry was applicable to the detection of larch tannin fractions as well. Moreover, Rhizopus sp tolerable to 61.4 g/L larch tannin was obtained through stepwise domestication, and the optimal conditions for Rhizopus sp to degrade larch tannin to catechin are: 49.0g/L larch tannin substrate, 10% (v/v) inoculation rate of 1.6×10~5 / mL spore solution, initial pH 4.5 at 31℃for 24 h. Under the conditions,catechin yield was 104mg, transformation rate of larch tannin into catechin was 49.1%.Microbial degradative process from larch tannin to catechin was studied for the first time. The results can lay a foundation for thorough investigation of vegetable tannin biodegradation mechanism, and supply reference to both finer and value-added utilization of vegetable tannins and removal of tannin pollution in...