%0 Journal Article
%T Engineering the reductive tricarboxylic acid pathway in Aureobasidium pullulans for enhanced biosynthesis of poly-L-malic acid.
%A Qin Z
%A Feng J
%A Li Y
%A Zheng Y
%A Moore C
%A Yang ST
%J Bioresour Technol
%V 393
%N 0
%D 2024 Feb 30
%M 38040309
%F 11.889
%R 10.1016/j.biortech.2023.130122
%X Aureobasidium pullulans produced poly-L-malic acid (PMA) as the main metabolite in fermentation but with relatively low productivity and yield limiting its industrial application. In this study, A. pullulans ZX-10 was engineered to overexpress cytosolic malate dehydrogenase (MDH) and pyruvate carboxylase (PYC) and PMA synthetase (PMS) using a high-copy yeast episomal plasmid with the gpdA promoter from Aspergillus nidulans. Overexpressing endogenous PMS and heterologous MDH and PYC from Aspergillus oryzae respectively increased PMA production by 19 % - 37 % (0.64 - 0.74 g/g vs. 0.54 g/g for wild type) in shake-flask fermentations, demonstrating the importance of the reductive tricarboxylic acid (rTCA) pathway in PMA biosynthesis. A. pullulans co-expressing MDH and PYC produced 96.7 g/L PMA at 0.90 g/L∙h and 0.68 g/g glucose in fed-batch fermentation, which were among the highest yield and productivity reported. The engineered A. pullulans with enhanced rTCA pathway is advantageous and promising for PMA production.