PRODUCTION AND CHARACTERIZATION OF FERULIC ACID ESTERASE-ACTIVITY IN CRUDE EXTRACTS BY STREPTOMYCES-AVERMITILIS CECT-3339

Streptomyces avermitilis CECT 3339 produces extracellular ferulic acid esterase (FAE) activity during growth on a range of lignocellulose su bstrates. Maximal levels of FAE activity were detected in culture filt rates from S. avermitilis CECT 3339 grown in media containing wheat br an and yeast extract as carbon and nitrogen sources respectively. Bioc hemical characterization of this enzyme activity revealed that it was 100-fold higher when wheat bran was pretreated with Celluclast (a mix of hydrolytic enzymes). FAE was found to be end-product-inhibited. Cha racterization of the properties of the enzyme showed that FAE exhibite d an activity optimum pH at 6 with pH stability between pH 6 and 8. Th e optimum temperature was 50 degrees C while the temperature stability was between 30 degrees C and 40 degrees C, with rapid inactivation at 60 degrees C and above. The characteristics and stability of FAE from S. avermitilis CECT 3339 suggest a potential role for this enzyme in combination with endoxylanases for the upgrading of plant-residue sila ge and for biopulping.