【摘要】 <正> 在自然界硫的转化过程中,能使硫或硫的不完全氧化物转化成为硫酸等产物,并在体内不累积硫粒而在土壤中起主要作用的硫化细菌,基本上只有一属,那就是硫杆菌属(Thiobacillus Beijerinck)。硫杆菌属在其生命活动过程中经转化而生成的硫酸,能使土壤中不溶性的矿质盐类,如磷酸钙等转化成为容易被植物吸收利用的可溶性矿质盐类,更多还原

【Abstract】 Three species of Thiobacillus have been isolated and cultivated in our laboratory from marine mud collected at low tide near a pier of Tsingtao. The pure cultures are: (1) Thiobacillus thioparus, (2) T. thiooxidans and (3) T. denitrificans.Enrichment cultures of T. thioparus have been obtained by inoculating 2-3g, of marine mud to a shallow layer of the following medium: Na2S2O3.7H2O, 1.0%; KH2PO4, 0.4%; K2HPO, 0.4%; MgS04.7H2O, 0.08%; NH4C1, 0.4%; Fe++(FeSO4) and Mn++(MnSO4), in trace; and water 100 ml.. After the culture is cultivated at 25-30C for 3-4 days, the medium becomes turbid and acid, and the pH reduced from original 7.3 to3. A loopful is taken from the culture and streaked on an agar medium with same coposition. Within 1-2 days, opaque colonies appear with a white and pale yellow precipitated sulfur colonies. If the cultivation is progressing, a small orange tint ap-peares in the center of the larger colonies. Repetition of streaking of a single colony will be able to obtain a pure culture. The microorganism have been characterized as an obligatory autotrophy, aerobic with an optimal pH for growth from neutral to weak alkaline.T. thiooxidans have been isolated by inoculating 2-3g. of marine mud to a flask containing 50 ml. of the following enrichment culture medium: elemental sulfur, 1.0%; (NH4)2SO4, 0.02%; KH2PO, 0.4%; MgSO4.7H2O, 0.05%; CaCl2,0.025%; FeSO4.7H2O, in trace; water, 100 ml. pH 3. After the culture is cultivated at 25-30℃ for 2-3 days or longer, the culture fluid becomes acid and turibid. Within two weeks pH drop to below 2, thereby assuming the predominance of the microorganim. A drop is taken from the culture fluid and transfer to a new medium. A pure culture is obtained by repetition of the procedure for 2-3 times.The microorganism is characterized as strictly autotrophic, obligatory aerobic with optimum reaction at 2.0-3.5. This microorganism produce more acid, by oxidation of sulfur, and to live in a more acid medium than any other microorganism ever reported.T. denitrificans have been isolated by inoculating 2-3 g. of marine mud to a glass stoppered bottle filling completely with the following medium: Na2S2O3-5H2O, 0.5%; KH2PO4, 0.2%; KNO3, 0.1%; NaHCO3, 0.1%; MgCl2.6H2O,0.05%; NH4C1, 0.05%; FeSO4.7H2O, 0.001%; water, 100 ml.; pH 7-7.6. After the culture is cultivated at 25-30℃ for 2-3 days, the culture fluid becomes turbid and gas bubble evolve from the sediment. Then 2/3 of the fluid is poured off and the bottle is filled again with the new medium. Repetition of pouring for 4 times, thereby assuming the predominance of T. denitrijicans. A loopful of culture fluid is then streaked on an agar plate on the same composition and incubated in vacuum discator filling with CO2. One week later, transparent, small, roud colonies appear. Taking from a single colony is then streak again on agar plate for purity. T. drnitrificans is characterized as facultative anaerobic or even microaerophilic, under anaerobic conditions nitrate is reduced to N2. A mixture of T. thiooxidans and T. thioparus including elemental sulfur used as a bacterial fertilizer for the reformation of strong alkaline soil is suggested and the Thiobacillus can be used as a standard culture for the detection of sulfur and metallic ore.更多还原