Abstract: In order to investigate the biological activity of Bacillus sp. glycosyl hydrolase GH489, the target gene gh489 was amplified by designing specific primers,the recombinant GH489 protein was expressed using the Escherichia coli prokaryotic expression system, and the target protein was isolated and purified using histidine tags. The acaricidal activity of Bacillus sp. glycosyl hydrolase GH489 against Tetranychus urticae was detected. The results showed that the recombinant GH489 protein expressed by Escherichia coli BL21 （DE3） was a soluble protein with a molecular weight of approximately 57 kDa. The purified GH489 recombinant protein showed good acaricidal activity,after 24 hours of treatment, the half lethal concentration （LC₅₀） of Tetranychus urticae was 30.296 μg/mL, and after 48 hours of treatment, the half lethal concentration （LC₅₀） of Tetranychus urticae was 21.212 μg/mL.

Key words: Bacillus sp., glycosyl hydrolase, expression, protein purification, acaricidal activity