Breeding high-yield pullulan engineering strains of Aureobasidium pullulans by ARTP mutagenesis and transcriptome analysis

Abstract

Abstract Pullulan is a microbial exopolysaccharide produced by Aureobasidium sp. with excellent physical and chemical properties, resulting in great application value. In this study, a novel strain of Aureobasidium pullulans with high pullulan yield up to 51.03 ± 1.03 g·L− 1 isolated from the rhizosphere soil of plants in Taihu Lake in Wuxi, China was subjected to atmospheric and room temperature plasma (ARTP) mutagenesis, followed by selective and optimization to obtain high-yield and high-quality strains. Finally, two pullulan high-yielding and stable genetic mutants Mu0816 and Mu1519 were obtained, with polysaccharide yields after 72-hour fermentation were of 58.71 ± 0.78 and 60.03 ± 0.75 g·L− 1, representing 15.05 and 17.64% increases compared with the original strain, respectively. Transcriptome sequencing was performed on the mutants and the original strain. Transcriptional analysis revealed that the high expression of abhd, gh18 and spMFS in the mutants may be related to the synthesis and secretion of pullulan. These results demonstrated the effectiveness of ARTP mutagenesis in A. pullulans, providing a basis for the investigation of genes related to pullulan production and metabolism.