A rod-shaped, Gram-negative chlorpyrifos-methyl (CM) degrading bacterium (designated strain KR200) was isolated from a Korean rice paddy soil and was further tested for its substrate specificity against 11 insecticides and its sensitivity against eight commercial antibiotics. Based on morphological, biochemical, and molecular characteristics, this bacterium showed greatest similarity to members of the order Flavobacteriales and was shown to be most closely related to members of the Chryseobacterium proteolyticum group. Strain KR200 hydrolyzed CM to 3,5,6-trichloro-2-pyridinol (TCP) but could not degrade TCP further. The isolate was also able to degrade chlorpyrifos, dicrotophpos, monocrotophos, and carbaryl at 300 μg mL–1 but diazinon, dimethoate, and furathiocarb at 100μg mL–1. The ability to degrade CM was found to be encoded on the chromosome. Genes encoding resistance to amphotericin B, polymixin B sulfate, and tetracycline were also located on the chromosome. This bacterium merits further study as a potential biological agent for the remediation of soil, water, or crop contaminated with organophosphorus (OP) compounds because of its greater biodegradation activity and its broad specificity against a range of OP insecticides.

뿌리혹선충의 화학적 방제를 대체할 수 있는 친환경적 선충방제제 개발을 위해 아미노산의 활용 가능성을 검토하고 케라틴 단백질로 구성된 닭우모 단백질로부터 추출한 가수분해물(chicken feather protein hydrolysate, CPH)의 고구마뿌리혹선충(Meloidogyne incognita)에 대한 증식억제 효과를 검정하였다. 고구마뿌리혹선충 2령 유충을 대상으로 19종의 아미노산을 이용하여 유충 치사력을 실내 검정한 결과, L-asparagine, L-aspartic acid, L-methionine, L-tyrosine 및 L-cysteine은 50 mM 농도에서 50% 이상의 유충 치사율을 나타내었다. 케라틴 단백질 분해세균 Chryseobacterium sp. FBF-7 균주는 실험실 규모의 6ℓ 발효조에서 배양 3일 후 75%의 닭우모분을 분해하였으며, CPH에 함유된 17종 아미노산의 총 함량은 1,661 μmol/㎖ 이었다. CPH의 고구마뿌리혹선충 알 부화 억제율과 2령 유충 치사력을 실내 검정한 결과, 1/100 희석액 처리 시, 24일 후 61%의 알 부화 억제율, 72시간 후 67%의 유충 치사력을 나타내었다. 토마토 포트 재배시험 토양에 CPH 1/100 희석액을 15일 간격으로 4회 처리한 결과, 토양 내 유충밀도 64%, 난낭수가 61% 감소되었다. 수박시설재배지에서 고구마뿌리혹선충에 대한 방제효과 시험을 수행한 결과, CPH 1/100 희석액 처리구에서는 토양 내 유충밀도와 난낭수가 무처리구에 비해 50% 억제되었으며, CPH 1/50 희석액 처리구에서는 토양 내 유충밀도와 난낭수가 60% 억제되었다. 따라서 Chryseobacterium sp. FBF-7에 의해 생산된 닭우모 단백질 가수분해물은 작물 생육기간에 사용가능한 고구마뿌리혹선충 방제제로 활용 가능하리라고 판단된다.

The Organophosphorus pesticides are widely used for agricultural and domestic purposes due to their relatively low persistence in the environment. Chlorpyrifos-methyl (CM) is used at a rate of over 14 million pounds per year in US agriculture, ranking it as the second most heavily used pesticide. This study aimed at isolating bacteria from soil and determining their ability to degrade CM and identify the intermediates in culture broth. Bacteria capable of degrading CM was isolated by enrichment culture. Chryseobacterium sp. strain KR200 degraded CM up to 91.58% in 7days. Studies with CM in liquid culture of Chryseobacterium sp. strain KR200 demonstrated that the isolate hydrolyzed CM to 3,5,6-trichloro-2-pyridinol, and utilized this compound for growth and energy. We performed SDS-PAGE and two-dimensional gel electrophoresis and identified proteins whose expression pattern is affected by CM using mass spectrometry. The results revealed various proteins that can be grouped according to their respective cellular function. These results highlight the potential of this bacterium to be used in the clean up of contaminated pesticide waste in the environment.