Highly efficient improvement of pigment production by accelerating starch hydrolysis in CICC41233.

To investigate the relationship between starch hydrolysis and pigments (MPs) production, the α-amylase gene () from was heterologously expressed in CICC41233, and we obtained a positive transformant named Amy9. In Amy9, the α-amylase activities were 6.65- and 4.26-fold higher at 72 h and 144 h, respectively, than those in the parent strain with the glucose as solo carbon medium. Surprisingly, in the MPs fermentation medium with rice powder as solo material, Amy9 completely degraded starch at 48 h, while 43.93 and 7.29 mg/mL starch remained at 48 and 144 h, respectively, in the parent strain. Amy9 accelerated starch hydrolysis, which enhanced biomass and also increased total MPs by 132% after 144 h. Compared with CICC41233, the relative gene expression levels, as determined by a quantitative real-time polymerase chain reaction analysis, of encoding ATP-citrate lyase subunit 2, encoding polyketide synthase, and encoding the fatty acid synthase beta subunit increased by 33.14, 145.18, and 32.15%, respectively, after 144 h in Amy9. The up-regulated expression of these key genes in MPs synthesis contributed to the large increase in MPs production. This interesting work provided us with a new idea and a new target for the study of the MPs production.