Microbial mutagenesis by atmospheric and room-temperature plasma (ARTP): the latest development

Although rational genetic engineering is nowadays the favored method for microbial strain improvement, random mutagenesis is still in many cases the only option. Atmospheric and room-temperature plasma (ARTP) is a newly developed whole-cell mutagenesis tool based on radio-frequency atmospheric-pressure glow discharge plasma which features higher mutation rates than UV radiation or chemical mutagens while maintaining low treatment temperatures. It has been successfully applied on at least 24 bacterial and 14 fungal species, but also on plants, dinoflagellates, and other microbial communities for the improvement of tolerance to medium components, to increase cellular growth and production of cellular biomass, to enhance enzyme activity, and to increase the production of various chemicals. Achievements like 385.7% of acetic acid production enhancement in Acetobacter pasteurianus give this new mutagenesis tool a promising future. However, certain questions remain regarding optimal operational conditions, the effects at subcellular levels, and standard operation procedures, which need to be addressed to facilitate applications of ARTP in microbial breeding and other fields such as evolution of enzymes.