Chitinase을 생산하는 곤충병원미생물 Metarhizium anisopliae HY-2(KCTC 0156BP)의 토양해충 생물검정

Solid state fermentation was performed for the production of entomopathogenic fungus Metarhizium anisopliae HY-2 using wheat bran media containing rice bran. Fungal growth in a solid state fermentation system was estimated by viable cell count, spore count, and mycelial biomass. It was used chemical method measuring N-acetyl-glucosamine (chitin) content for estimating of mycelial biomass. In static flask culture, viable cell reached 2.40 ${\times}$ $10^8$ cfu/g at 23 days of culture at $27^{\circ}C$ and then mycelial biomass was 41.59 mg/g. Specific growth rate(${\mu}$ max) was 0.0418 $h^{-1}$ between 3 and 9 days when estimated by viable cell count and was 0.00976 $h^{-1}$ between 9 and 17 days when N-acetylglucosamine content was measured. Viable cells reached 1.12 ${\times}$ $10^8$ cfu/g in polypropylene-bag at 28 days of culture at $27^{\circ}C$. Formulated microbial pesticide containing M. anisopliae HY-2 were tested their bio-activity against Chestnut Brown Chafer (Adoretus tenuimaculatus). The protection rate of the liquid culture showed 13 ${\sim}$ 26 % with 1st to 3rd instar, and spore suspension of M. anisopliae HY-2 showed 56 ${\sim}$ 64%. Conidia produced by large scale solid-state fermentation showed 20 ${\sim}$ 27 % activity 60 ${\sim}$ 64 % with M. anisopliae HY-2.

균체 생산성 실험과 chitinase 생산성 실험을 비교해 볼 때, chitinase만을 생산하는 조건 에서는 배지성분에 chitin을 첨가해 주는 것이 좋으나, 해충 방제용으로 살균력을 증진시키기 위하여 균체량과 chitinase의 생성량 및 산업적, 경제적 사용이 용이한 배지를 고려할 때에는 쌀겨와 밀기울이 첨가된 배지가 좋은 배지임을 알 수 있었다. 또한 이 배지를 이용하였을 경우 균체는 1X$10^8$ cfu/g, chitinase는 370mU/g로 생산되었으며 생물검정결과 53-64%의 탁월한 살충효과를 확인 할 수 있었다.