化能自养型微生物利用太阳能途径的实验研究

针对自然界中天然半导体矿物和化能自养微生物之间的能量交换途径进行了详细的实验研究.半导体光电化学实验结果显示,天然半导体矿物在光照情况下产生的光生电子可将Fe3+还原为Fe2+,其中金红石光催化还原Fe3+的效率为12.5%,闪锌矿为7.86%,该过程通过天然半导体矿物的日光催化作用实现了太阳光能→电能→化学能的转化;控制电势的微生物电化学反应实验结果显示,化能自养型微生物A.f.菌的细胞增加量与外界电子传入而生成的Fe2+的量呈线性关系,且有外来电子传入实验组的A.f.生长量是无电子传入组的441%,该过程通过菌的生长代谢作用实现了化学能→生物质能的转化.进一步的光电化学和微生物电化学耦合实验结果证明,在太阳光和天然半导体矿物共同作用下,A.f.菌的对数生长期由无光时的36 h延长到72 h,同时细菌的生长在该能量转化过程中得到了明显促进.在天然闪锌矿催化条件下,有光条件的A.f.菌数量增加到无光条件的1.90倍;而在金红石催化条件下,有光条件的A.f.菌数量增加到无光条件的1.69倍.实验结果说明,在以天然半导体矿物为媒介的情况下,化能自养微生物可间接利用太阳能来获得自身的生长繁殖所需的能量,这一过程也实现了太阳光能→电能→化学能→生物质能的能量转化途径.

Experimental researches on the pathway of the chemoautotroph microbes utilizing solar energy

The energy exchange between natural semiconductor minerals and chemoautotroph microbes was investigated in details in this paper. Photo-electrochemical experiments indicate that the photoelectrons generated by natural semiconductor minerals in solar light can reduce ferric ion to ferrous ion. The reduction efficiency of natural rutile is 12.5% and that of natural sphalerite is 7.86%. This process, which is driven by the photo-catalysis of natural semiconductor minerals, realizes the energy transformation from solar energy to electric energy and finally to chemical energy as stored in the form of ferrous ion. The potential control experiment shows a linear relationship between the amounts of cell growth (A. f.) and the electrons needed for ferrous reduction. Meanwhile the amount of A. f. with electrons flowing in is 4.41 times greater than that of the control group. This process realizes the energy transform from chemical energy to biomass energy by microbe metabolism. Further experiments, which integrate the two processes by an electrochemical cell, indicate that the logarithm growth period of A. f. is extended from 36 h under the dark condition to 72 h under the light condition. Meanwhile, an obvious improvement of cell growth is observed. The concentration of A. f. under the light condition is 1.90 times higher than that under the dark condition when the mineral is sphalerite, while the number is 1.69 times higher when the mineral is rutile. The results demonstrate that the growth of chemoautotroph microbes can be favored by an indirect utilization of solar energy under the assistance of semiconductor photo-catalysis, thus realizing the energy transformation from solar energy to electric energy, chemical energy and finally to biomass energy.