Dissimilatory Fe(III) reduction characteristics of paddy soil extract culturestreated with glucose or fatty acids

Dissimilatory Fe(III) reduction is a universal process with irreplaceable biological and environmental importance in anoxicenvironments. Our knowledge about Fe(III) reduction predominantly comes from pure cultures of dissimilatory Fe(III) reducingbacteria (DFRB). The objective of this study was to compare the e ects of glucose and a selection of short organic acids (citrate,succinate, pyruvate, propionate, acetate, and formate) on Fe(III) reduction via the anaerobic culture of three paddy soil solutions withFe(OH)3 as the sole electron acceptor. The results showed significant di erences in Fe(III) reduction among the three paddy soilsolutions and substrate types. Bacteria from the Sichuan paddy soil responded quickly to substrate supply and showed higher Fe(III)reducing activity than the other two soil types. Bacteria in the Jiangxi paddy soil culture solution could not use propionate as a sourceof electrons for Fe(III) reduction. Similarly, bacteria in the Jilin paddy soil culture could not use succinate e ectively. Pyruvate wasreadily used by cultures from all three paddy soil solutions, thus indicating that there were some similarities in substrate utilizationby bacteria for Fe(III) reduction. The use of glucose and citrate as substrate for dissimilatory Fe(III) reduction indicates importantecological implications for this type of anoxic respiration.