Department of Biotechnology, University of New South Wales, P.O. Box 1, Kensington, New South Wales 2033, Australia.
Appl Environ Microbiol. 1991 Apr;57(4):1114-20. doi: 10.1128/aem.57.4.1114-1120.1991.
Microbial manganese oxidation was demonstrated at high Mn concentrations (5 g/liter) in bacterial cultures in the presence of a microalga. The structure of the oxide produced varied depending on the bacterial strain and mode of culture. A nonaxenic, acid-tolerant microalga, a Chlamydomonas sp., was found to mediate formation of manganite (gamma-MnOOH). Bacteria isolated from associations with crude cultures of this alga grown in aerated bioreactors formed disordered gamma-MnO(2) from Mn at concentrations of 5 g/liter over 1 month, yielding 3.3 g of a semipure oxide per liter. All algal-bacterial cultures removed Mn from solution, but only those with the highest removal rates formed an insoluble oxide. While the alga was an essential component of the reaction, a Pseudomonas sp. was found to be primarily responsible for the formation of a manganese precipitate. Medium components-algal biomass and urea-showed optima at 5.7 and 10 g/liters, respectively. The scaled-up culture (50 times) gave a yield of 22.3 g (53 mg/liter/day from a 15-liter culture) of semipure disordered gamma-MnO(2), identified by X-ray diffraction and Fourier transform infrared (FTIR) spectroscopy, and had a manganese oxide O/Mn ratio of 1.92. The Mn(IV) content in the oxide was low (30.5%) compared with that of mined or chemically formed gamma-MnO(2) (ca. 50%). The shortfall in the bacterial oxide manganese content was due to biological and inorganic contaminants. FTIR spectroscopy, transmission electron microscopy, and electron diffraction studies have identified manganite as a likely intermediate product in the formation of disordered gamma-MnO(2).
在含有微藻的细菌培养物中，在高锰浓度（5 克/升）下证明了微生物锰氧化作用。所产生的氧化物的结构取决于细菌菌株和培养方式。从在通气生物反应器中生长的这种藻类的粗培养物的共生体中分离出的一种非共生、耐酸的微藻被发现介导了菱锰矿（γ-MnOOH）的形成。从浓度为 5 克/升的锰中，在一个月的时间内，从浓度为 5 克/升的锰中分离出的细菌在浓度为 5 克/升的锰中形成无定形的 γ-MnO 2 ，每升产生 3.3 克半纯氧化物。所有藻类-细菌培养物都从溶液中去除了锰，但只有那些去除率最高的培养物形成了不溶性氧化物。虽然藻类是反应的必要组成部分，但发现 Pseudomonas sp. 主要负责形成锰沉淀物。培养基成分-藻类生物质和尿素-分别在 5.7 和 10 克/升时表现出最佳效果。扩大培养（50 倍）得到了 22.3 克（从 15 升培养物中每天 53 毫克/升）的半纯无序 γ-MnO 2 ，通过 X 射线衍射和傅里叶变换红外（FTIR）光谱鉴定，其氧化锰 O/Mn 比为 1.92。氧化物中的 Mn(IV)含量较低（30.5%）与开采或化学形成的 γ-MnO 2 （约 50%）相比。细菌氧化物中锰含量的不足是由于生物和无机污染物造成的。FTIR 光谱、透射电子显微镜和电子衍射研究表明，菱锰矿是形成无序 γ-MnO 2 的可能中间产物。
