Vital interplay between microorganisms and extracellular minerals
Some minerals abundant in soils and in aquatic and subsurface sediments electronically support microbial growth by supplying electrons or storing them as "environmental batteries," according to this new review article. Microbial cells derive chemical energy from metals associated with minerals outside the cell wall, but in many cases the microbial cell envelope is physically impermeable to minerals, or is not electrically conductive. Because of these barriers some microorganisms have evolved strategies to exchange electrons with extracellular minerals. The article outlines advances in understanding the mechanisms that allow needed electron exchange. Some mechanisms involve redox and structural proteins that form extensive electron transfer pathways. Others rely on microbial nanowires, which are conductive bacterial appendages anchored in the cell envelope, or they rely on ridged "cable bacteria."
