In this study, the long-acting mechanism of reactive species was investigated for enhanced ethanol production of Saccharomyces cerevisiae. The results indicated that short-lifetime active species from gas phase plasma dissolved into various liquid microenvironments with different media (water, buffer, medium, and cells), forming different types and amounts of reactive species in multi-scale microenvironments, such as extracellular reactive nitrogen species, endocellular reactive oxygen and nitrogen species. The sustained elevation of cytoplasm calcium concentration with treatment time depended on the activated calcium channels of Cch1p/Mid1p in cell membrane and Yvc1p in vacuole membrane by these species. Accordingly, the Ca2+ increase promoted the H+-ATPase expression. Consequently, 75.6% ATP hydrolysis induced about 5 fold NADH increase compared with the control. Ultimately, the bioethanol yield increased by 34.2% compared to the control. These results promote the development of atmospheric cold plasma as a promising bio-process enhancement technology for improved target product yields of microbes in fermentation industry.
Keywords: Air cold plasma; Bioethanol; Calcium channel; Proton pump; Reactive species.
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