INDUCTION OF FERULIC ACID ESTERASE AND XYLANASE ACTIVITIES IN STREPTOMYCES-AVERMITILIS UAH30

Ferulic acid esterase activity (FAE) was detected, along with xylanase activity, in culture supernatants from Streptomyces avermitilis UAH30 grown in the presence of the lignocellulosic substrates, oat spelt xy lan, wheat bran without starch and sugar cane bagasse. The maximum act ivity was detected with wheat bran (1.75 mU ml(-1)). No correlation be tween FAE activity and the amount of esterified ferulic acid present i n the substrate was observed. The addition of either glucose, mannitol or glycerol to the culture medium containing oat spelt xylan resulted in a reduction of 40-75% in the xylanase activity detected in culture supernatants. FAE activity could only be detected in supernatants fro m cultures grown in the presence of glycerol and mannitol, when commer cially available xylanases were added to the assay. These results high light the importance of assaying for FAE activity in the presence of h igh levels of xylanase activity. (C) 1998 Federation of European Micro biological Societies. Published by Elsevier Science B.V.