CHROMOSOMAL GENE INTEGRATION AND ENHANCED XYLANASE PRODUCTION IN AN ALKALOPHILIC THERMOPHILIC BACILLUS SP (NCIM-59)

Chromosomal integration and xylanase gene amplification were demonstrated for the first time in an alkalophilic thermophilic Bacillus sp. (NCIM 59). The integrants were characterized by larger zone of xylan clearance than the parent culture and hybridization with vector (pUC8) DNA. Repeated transformation strategy was used for further amplification of the xylanase gene. The results of Southern blot analysis indicated the occurrence of homologous recombination in the 6.5 kb xylanase gene region of the genomic DNA and suggested a non campbell mode of recombination. The integrants were checked for xylanase production up to ten subcultures and consistently showed two fold higher xylanase activity than the parent strain with the maximum xylanase productivity (U/ml/h) at 16 h. © 1993 Academic Press, Inc.