Material Processing Using Microorganisms (2nd Report, Investigation on Biorecycling of Iron Red Rust)

Abstract

Based on an indication in the previous research that there is an ocean bacterium which can reduce iron red rust to magnetite extracellularly, it is attempted to develop a new recycling process employing such kind of bacteria. Two methods for producing very fine magnetite powder from red rust are presented by making up an artificial environment and shown to be successful. Bacteria participating in magnetite production are examined in detail, and are found to be microaerobic ammonia-oxidizing bacteria (coccus and bacillus), regarded as new types different from the GS-15 bacterium reported earlier. Their role is clarified and a mechanism of magnetite formation is presented.