Basalt rock weathering by Peribacillus simplex from Wudalianchi volcanos in NE China and implications for Fe and Si biogeochemical cycling

Abstract

Bacteria have an important role in weathering the different rocks, but little is known about the mechanism of microbial weathering in basalt rocks. In the present study, Peribacillus simplex WS-L19 isolated from Wudalianchi volcanos exhibits the highest Fe and Si rock dissolution, which revealed unique weathering ability. The optimal weathering conditions of LB medium diluted at 30.9%, the rotation speed of 127.2 rpm, and temperature at 36.6 °C, resulted in the Fe and Si releases of 1.70 ± 0.09 μg/mL and 20.11 ± 1.13 μg/mL, respectively. Simultaneously, complex ligands such as organic acids (tartaric acid, formic acid, lactic acid and succinic acid), siderophores, and biofilm were also found to be involved in weathering processes by P. simplex WS-L19. Kinetics study of Fe and Si release indicated that the weathering processes of volcanic rocks mediated by P. simplex WS-19 fits a Hyperbl model. Mineralogical analysis showed a decrease in Fe releasing ratio by 44.65% and an increase in Si releasing ratio by 28.45%, showing that Fe is more accessible than Si. P. simplex WS-L19 had a significant weathering effect on biotite, and Si-O bonding vibration might contribute to weathering. The results suggest that indigenous P. simplex WS-L19 plays a role in weathering Wudalianchi volcanos and provides new insights into the Fe and Si biogeochemical cycling of basalt rocks.