(67c) Engineered the Yeast-like Fungus Aureobasidium Pullulans for Carbon-Economic Biosynthesis of Polymalic Acid from International Resources

The low-cost manufacturing of bio-based natural polymeric materials and health products is a crucial aspect in the bioeconomy. The development of microbial strain resources with independent intellectual property rights holds significant importance. Leveraging the resources of the yeast like fungi Aureobasidium pullulans, our group actively cooperated with Professor Zeng Quan from the University of Connecticut to conduct research on the Chinese and American biocontrol preparations against pear fire blight disease. Considering the biosynthesis characteristics of polymalic acid, a natural bio-material produced by A. pullulans, we have partnered with researchers in Burundi to screen the resource and mine functional genes for heat-resistant A. pullulans in China and Africa. The genetic transformation system, signal regulation engineering, genome simplification, carbon emission reduction modularization engineering and other transformation strategies were developed for this characteristic chassis fungus. Additionally, we have devised resting cell fermentation technology using ethanol as sole substrate and a carbon emission reduction fermentation method driven by a combination of glycerol and ethanol resulting in 30% CO2 emission reduction. The engineered A. pullulans strain with deleted by-product pathways exhibits advantageous for large-scale commercialization of PMA and L-MA production, resulting in the advancement of novel bio-manufacturing technology for producing L-malic acid through acid hydrolysis of natural polymalic acid. The industrialization technology was achieved for aqueous phase crystallization of L-malic acid ensuring product quality without impurities such as succinic acid.