Ethanol and Xylitol Production from Xylanase Broth of Thermomyces Lanuginosus Grown on Some Lignocellulosic Wastes using Candida tropicalis EMCC2

Abstract

Four different strains of Thermomyces lanuginosus were screened for cellulase-free xylanase enzyme. These were: Thermomyces lanuginosus A72, T. lanuginosus H72, T. lanuginosus U72 and T. lanuginosus YMN72.The potentiality of these strains to produce cellulase-free xylanase was screened on four different natural lignocellulosic substrates. Incubation period lasted for 7 days at 45 ºC. Thermomyces lanuginosus A72 and T. lanuginosus YMN72 generally exhibit a relatively higher xylanase activity as compared with other fungal strains when grown on cane bagasse and corn cobs; respectively. T. lanuginosus A72 showed xylanase activity (411 U/ml) on cane bagasse (1.0%) as carbon source, while T. lanuginosus YMN72 produced highest xylanase activity (428 U/ml) when grown on corn cobs (1.5%) as carbon source when incubated at 45ºC for seven days of growth. Both of the experimental fungal strains reached a maximum value of xylanase activity at slightly neutral pH (6.6) giving (442 U/ml & 723 U/ml respectively). Sodium nitrate (0.3 % w/v) was the best nitrogen source for T. lanuginosus A72 where xylanase activity reached 563U/mg., while ammonium nitrate (0.1% w/v) was the best nitrogen source for T. lanuginosus YMN72 giving xylanase activity 946U/ml. Gamma radiation affected xylanase produced by the two experimental strains. Thus radiation dose (1.0KGy) was the best for the production of xylanase by T. lanuginosus A72 giving activity (1082U/ml) with increasing 179% as compared with control value. On the other hand results showed that radiation dose (0.9KGy) was the best for the production of xylanase by T. lanuginosus YMN72 giving activity (1173U/ml) with increasing 121% as compared with control value. Maximum saccharification was obtained from treatment of cane bagasse by partially purified xylanase from T. lanuginosus A72 and T. lanuginosus YMN72 after 24 hrs of incubation. The maximum production of ethanol and xylitol were obtained after fermentation time 48 and 24 hrs giving (22.48 and 13.54 g/l) using enzyme broth of T. lanuginosus YMN72 using Candida tropicalis EMCC2.