CHEMOHETEROTROPHIC SULFUR-OXIDIZING MICROORGANISMS OF A TERAI SOIL .1. OXIDATION OF INORGANIC AND ORGANIC SULFUR BY MICROORGANISMS, ISOLATED IN SUCROSE-SODIUMTHIOSULFATE AGAR

Among twenty one chemoheterotrophic sulfur-oxidising microorganisms, i solated in sucrose-sodiumthiosulfate agar plates from a representative Indian Terai Soil - a Himalayan foot hill soil of the Order Mollisol (Typic Haplaquept). Thirteen isolates were bacteria, twelve belong to the genus Bacillus, and one to Micrococcus, three actinomycetes to the genus Streptomyces. Five isolates were fungi - two of the genus Penic illium, and three of the genus Aspergillus. Of these, the efficient su lfur oxidisers were Bacillus spp - TSB5 and TSB6, Streptomyces sp. - T SA1, and Aspergillus spp. - TSF3 and TSF5. In general, the oxidation b y the isolates was essentially higher from the inorganic sulfur source , sodiumthiosulfate than from the organic sulfur source, L-cystine. Th e overall efficiency of the genera decreases in following order Asperg illus, Penicillium, Streptomyces, Bacillus and Micrococcus.