ABSTRACT
A fungus CQ31 isolated from soil samples was identified as Chaetomium sp.. This strain produced effectively xylanases utilizing several liguocellulosic materials in the solid-state fermentation (SSF), and corn straw was the best carbon source. The results of single-factor-experiment showed that the corn straw as the carbon source, tryptone as the nitrogen source, initial moisture content of 80% and initial pH 9.0 were the optimal conditions for xylanase production. Under the optimized conditions, it produced xylanase which was 4897 U/g dry substrate while mannanase was 803 U/g dry substrate after 7 days of cultivation. Therefore, xylanase and mannanase production by Chaetomium sp. CQ31 in SSF possess potential for commercial applications.
ABSTRACT
The cloning and expression of a?-galactosidase gene(TM_0310)from Thermotoga maritima MSB8 was studied.The gene consists of 2019 bp,and the translated protein encodes 672 amino acids and its molecular mass is approximately 78.972 kD.The homology analysis of the deduced amino acid sequences showed that the enzyme shared 95%identity with a putative?-galactosidase from Thermotoga petrophila RKU-1 and a?-galactosidase from Thermotoga sp.RQ2.The galactosidase activity was up to 2.08 U/mg after the recombinant E.coli BL21 was induced by IPTG.The crude lysate remained about 70%activity after treated at 80℃for 10 min,indicating that the recombinant enzyme is thermostable and may be used at high temperatures.