The utilization of solar energy by non-phototrophic microorganisms through semiconducting minerals

Abstract:

Phototropy and chemotrophy microorganisms compose the whole microbe world. As non-phototrophic microorganisms are excluded from phototrophy due to the lack of phototropic system. Here we introduce a novel pathway of microorganism energy utilization. The non-phototrophic microorganisms could get solar energy through semiconducting mineral photocatalysis. In simulated system, under simulated solar light semiconducting minerals, such as metal oxides and metal sulfides, generated photo electrons which could be used by non-phototrophic microorganisms to support their metabolisms. The growth of microorganism was closely related to photon quantity and energy and the microorganism growth and mineral light absorption spectra were fitted well under different light wavelengths. The overall energy efficiency from photon to biomass was 0.13‰ to 1.90‰. Further studies revealed that in natural soil systems, semiconducting mineral photocatalysis could influence the microbial population. This study provided the evidence to reveal a novel but long existed pathway in which the semiconducting mineral photocatalysis could stimulate the non-phototrophic microorganism metabolisms.