Biodegradation of Quinalphos by a Soil Bacterium-Bacillus subtilis

• 발행기관: 인간식물환경학회
• 저자명: Venkata Subba Reddy Gangireddygari Rajasekhar Reddy Bontha Bong-Nam Chung In-Sook Cho Ju-Yeon Yoon
• 간행물 정보: 『인간식물환경학회 학술대회』2020년 추계학술대회 자료집, 237~237쪽, 전체 1쪽
• 주제분류: 자연과학 > 자연과학일반
• 파일형태: PDF
• 발행일자: 2020.11.19

영문 초록

A widely used pesticide quinalphos (O, O-diethyl O-quinoxalin-2-yl phosphorothioate) may be an undesirable and persistent pollutant to non-target environments like rivers and other ecosystems. The objective of this study was to isolate a potential degradant bacterium of quinalphos from polluted soils and test its fitness under various culture conditions. A soil bacterium strain, capable of utilizing quinalphos as its sole source of carbon and energy was isolated from soil by enrichment method on a minimal salts medium (MSM). On the basis of morphological, biochemical and 16S rRNA gene sequence analysis the bacterium is a species of the genus Bacillus and it was closely related to Bacillus subtilis. Quinalphos degrading capabilities of this bacterium were assessed under different culture conditions. Quinalphos degradation data were analysed byusing a two-way ANOVA analysis with the Statistica v.10. Bacillus subtilis grew on quinalphos with a generation time of 32.34 min or 0.54 h in the logarithmic phase. Maximum degradation of quinalphos was observed with an inoculum of 1.0 optical density, around pH-7.5 and at an optimum temperature of 35-37°C. Among the additional carbon and nitrogen sources, carbon source-glucose and nitrogen source-yeast extract marginally improved the rate of degradation of quinalphos. Gas chromatography-mass spectrometry (GC-MS) analysis of the culture of B. subtilis grown on quinalphos indicated the formation of one main metabolite-quinoxaline. In conclusion, the B. subtilis strain discovered in this study has a unique combination of abilities to degrade quinalphos and it is therefore suitable candidate bioremediator of quinalphos polluted environments.

키워드

16S rRNA sequence analysis 2-hydroxyquinoxaline Bacillus subtilis GC-MS analysis Quinalphos