STRAIN IMPROVEMENT FOR THE PRODUCTION OF A THERMOSTABLE ALPHA-AMYLASE

Bacillus sp. MK716, a thermophilic and amylolytic soil isolate, produc ed a thermostable alpha-amylase active even at 100 degrees C. The enzy me yield was increased 40 times through mutagenesis with ethylmethane sulfonate. The mutated gene was cloned in Escherichia coli-pBR322 syst em, and the 4.8 kb cloned fragment was mapped with restriction enzymes . Subcloning in Bacillus subtilis of a 2.0 kb portion of the cloned fr agment resulted in 107 times increased enzyme yield. The recombinant p lasmid was completely stable in B. subtilis. (C) 1997 Elsevier Science Inc.