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High-level production of Monascus pigments in Monascus ruber CICC41233 through ATP-citrate lyase overexpression

Long, Chuannan, Zeng, Xu, Xie, Jian, Liang, Yumei, Tao, Jingjing, Tao, Qingqing, Liu, Mengmeng, Cui, Jingjing, Huang, Zhiwei, Zeng, Bin
Biochemical engineering journal 2019 v.146 pp. 160-169
ATP citrate synthase, Monascus ruber, acetyl coenzyme A, amination, amino acid metabolism, ammonia, biochemical pathways, biosynthesis, gene overexpression, genes, glycolysis, isoleucine, leucine, pigments, rice, sequence analysis, serine, starch, threonine, transcriptomics, valine
ATP-citrate lyase (ACL) plays a key role in the formation of acetyl-CoA, a crucial precursor for Monascus pigments biosynthesis. Whether ACL affects the pigments synthesis pathway in Monascus spp. is unknown. Here, we focus on acl1 and acl2 genes, encoding two subunits of ACL that were overexpressed in Monascus ruber CICC41233 to generate Monascus ruber ACL438469-4 and Monascus ruber ACL501969-11, respectively. Both acl overexpression strains significantly increased ACL activity, leading to elevate levels of acetyl-CoA. These strains completely degraded starch from rice powder after 4 days. Total Monascus pigments production was remarkably enhanced by 92.70% in M. ruber ACL438469-4 and 112.58% in M. ruber ACL501969-11 after 6 days. The red pigments in M. ruber ACL438469-4 and in M. ruber ACL501969-11 were more than that in parent strain. Transcriptome sequencing analysis of the acl overexpression strains vs the wild-type showed that differentially expressed genes were mainly involved in starch and glycolysis metabolism; valine, leucine, and isoleucine degradation; glycine, serine, and threonine metabolism; and Monascus pigment biosynthetic pathway. This implied metabolic flux for acetyl-CoA during pigment synthesis and NH3 for amination of red pigments. Thus, ACL modulated starch and amino acid metabolism to regulate Monascus pigments production in M. ruber.