東京湾海水より単離したピレン分解酵母  [in Japanese] Pyrene decomposing yeasts collected from sea water of Tokyo Bay  [in Japanese]

海洋環境中の多環芳香族化合物の生物修復を目的に,ピレン[Pyr]分解微生物を東京湾海水中から探索した。生理学的試験から,分解菌は酵母Dekkera bruxellensis,candida sp.と固定された。Pyr過飽和[4μg/mL,飽和濃度の50倍液,開放系]人工海水に酵母を添加したところ,5週間でPyr濃度が約38%に減少した。一方,滅菌処理酵母の添加ではPyrが開放系で約68%,閉鎖系で100%残存した。開放系ではPyrの揮発を差引いた約30%が酵母によって分解された。両酵母のPyr分解速度は1.4〜4.0×10^<-9>μg/CFU・h^<-1>であった。

Microbes which degrade pyrene, one of the major poly-aromatic hydrocarbons (PAHs), were searched for in seawater of Tokyo Bay as the first step of bioremediation for PAHs in the marine environment. The isolated microbes were classified to be yeasts, Dekkera bruxellensis and Candida sp., by a series of physiological identification tests. Pyrene (4μg/mL suspension, 50 times as much pyrene of saturated concentration to the media) was degraded to 38% in 5 weeks in an open system. 0n the other hand, pyrene concentration in the control (cells were autoclaved) stayed at exactly the same level in a closed system in 5 weeks, and decreased to 68% in the open system in the same time period. From these experimental results it can be concluded that the difference in pyrene concentration in the open system with and without yeasts (30% of original concentration) showed the amount degraded by yeasts. The degradation rate of the yeasts was calculated as 1.4-4.0×10^<-9>μg/CFU・h^<-1>.