CLOSTRIDIUM SPECIES AND GAMMA-BHC DEGRADATION IN PADDY SOIL

O2 at atmospheric pressure had an inhibitory effect on the BHC-decomposing ability of Clostridium rectum, strain S-17. The inhibition was reduced by the addition of the clay mineral bentonite to the culture, and by the presence of other soil microorganisms. The half-life of y-BHC under submerged conditions decreased with increase in numbers of anaerobic γ-BHC decomposers, and with increasing amounts of ninhydrin-positive materials in the soil. Alpha-BHC and γ-BHC decomposers multiplied following the addition of peptone to paddy soil from 103 and 104 to about 106 and 107 g-1 wet soil, respectively. Clostridium rectum, strain S-17, C. sporogenes, C. putrefaciens, C. bifermentans, C. lentoputrescens, C. butyricum, C. acetobutylicum and C. histolyticum could decompose γ-BHC, but none of them could decompose β- and δ-BHC. In flooded soil Clostridium spp. appeared to be the most widespread BHC decomposers. © 1979.