Effects of pigment and citrinin biosynthesis on the metabolism and morphology of Monascus purpureus in submerged fermentation.
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ABSTRACT:
SUBMITTER: Chai X
PROVIDER: S-EPMC7297905 | biostudies-literature |
REPOSITORIES: biostudies-literature
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Project description:Monascus purpureus YY-1 is widely used in food colorant production in China. Our previous study clearly illustrated the whole-genome data for YY-1 and provided useful insight into evolutionary research and industrial applications. However, the presence of citrinin, which has nephrotoxic, hepatotoxic, and carcinogenic activities, has attracted attention to the safety of Monascus products. In an effort to reduce the harmful effects of citrinin in Monascus-related products, a random mutant of M. purpureus YY-1 with low citrinin production (designated as "winter") was obtained in this study. To analyze the biosynthesis and regulation mechanisms of pigment and citrinin, a transcriptomic analysis of the M. purpureus YY-1 and winter strains was performed. Comparative transcriptomic analysis reveals pksCT, the essential gene for citrinin synthesis, showed a low expression level in M. purpureus YY-1 and winter, which suggested there might be isoenzymes in M. purpureus YY-1 that were responsible for the citrinin synthesis during evolution. In addition, changes in transcription factor expression may also influence the network regulating the citrinin synthesis pathway in M. purpureus. Moreover, the yields of pigments produced by the winter mutant were significantly increased. Repressing the central carbon metabolism and improving the acetyl-CoA pool can contribute to a high pigment yield, and enhanced NADPH regeneration can also lead to the metabolic flux of pigment production in M. purpureus. Investigations into the biosynthesis and regulation of citrinin and pigment production in M. purpureus will enhance our knowledge of the mechanisms behind the biosynthesis of fungal secondary metabolites.
| S-EPMC6031731 | biostudies-literature
Project description:Citrinin produced by Aspergillus, Penicillium, and Monascus species is a polyketide compound that has nephrotoxic activity in mammals and is bactericidal toward gram-positive bacteria. To avoid the risk of citrinin contamination in other fermentation products produced by Monascus purpureus, knowledge of the citrinin biosynthetic genes is needed so that citrinin-nonproducing strains can be generated. We cloned a polyketide synthase (PKS) gene from M. purpureus with degenerate primers designed to amplify the conserved region of a ketosynthase domain of a fungal PKS. A 13-kb genomic DNA fragment was identified that contained a full-length PKS gene (pksCT) of 7,838 bp with a single 56-bp intron. pksCT encodes a 2,593-amino-acid protein that contains putative domains for ketosynthase, acyltransferase, acyl carrier protein (ACP), and a rare methyltransferase. There was no obvious thioesterase domain, which usually is downstream of the ACP domain in multi-aromatic-ring PKSs. pksCT transcription was correlated with citrinin production, suggesting that the pksCT gene product was involved in citrinin biosynthesis. Homologous recombination between the wild-type allele and a truncated disruption construct resulted in a pksCT-disrupted strain of M. purpureus. The disruptant did not produce citrinin, but a pksCT revertant generated by successive endogenous recombination events in the pksCT disruptant restored citrinin production, indicating that pksCT encoded the PKS responsible for citrinin biosynthesis in M. purpureus.
| S-EPMC1168973 | biostudies-literature
Project description:Monascus pigments (MPs) display many beneficial biological activities and have been widely utilized as natural food-grade colorants in the food processing industry. The presence of the mycotoxin citrinin (CIT) seriously restricts the application of MPs, but the gene regulation mechanisms governing CIT biosynthesis remain unclear. We performed a RNA-Seq-based comparative transcriptomic analysis of representative high MPs-producing Monascus purpureus strains with extremely high vs. low CIT yields. In addition, we performed qRT-PCR to detect the expression of genes related to CIT biosynthesis, confirming the reliability of the RNA-Seq data. The results revealed that there were 2518 differentially expressed genes (DEGs; 1141 downregulated and 1377 upregulated in the low CIT producer strain). Many upregulated DEGs were associated with energy metabolism and carbohydrate metabolism, with these changes potentially making more biosynthetic precursors available for MPs biosynthesis. Several potentially interesting genes that encode transcription factors were also identified amongst the DEGs. The transcriptomic results also showed that citB, citD, citE, citC and perhaps MpigI were key candidate genes to limit CIT biosynthesis. Our studies provide useful information on metabolic adaptations to MPs and CIT biosynthesis in M. purpureus, and provide targets for the fermentation industry towards the engineering of safer MPs production.
| S-EPMC9965497 | biostudies-literature
Project description:Six Monascus purpureus (red mould) strains were cultivated on brown rice and millet as substrates. They underwent strain selection for high lovastatin and pigment production, and low citrinin mycotoxin production, with particular reference to potential for millet as substrate. For most of these strains, substrate dry matter loss was 54-60% on rice and 46-48% on millet, although the 'MOPU GS1' strain showed 18% and 17% dry matter loss, respectively. 'MOPU GS1' was also the only strain with detectable levels of lovastatin (1.3 and 1.6 mg lovastatin/g substrate dry weight [dw], respectively) and citrinin under the limit of detection. In the other strains, citrinin varied from 0.3 to 18.2 mg/g substrate dw. Among the six strains, 'EBY3' provided high pigment production when grown on rice, although it produced 1.1 mg citrinin/g substrate dw. Millet showed good potential as an alternative substrate to rice, due to higher lovastatin and lower citrinin production; however, rice was the better substrate for production of M. purpureus pigments.
| S-EPMC6582186 | biostudies-literature
Project description:M. purpureus YY-1 is widely used in food colorant production in China. In our previous study, the whole-genome information of YY-1 was clearly illustrated, which provided useful hints for evolution esearch and industrial applications. However, the presence of citrinin, which has nephrotoxic, hepatotoxic, and carcinogenic activities, attracts people′s attention to the safety of Monascus products. In order to reduce the harm of citrinin in Monascus related products, in this study, a random mutant of M. purpureus YY-1, with scarce citrinin production (designated as winter) was obtained. To analyze the biosynthesis and regulation mechanism of pigment and citrinin, transcriptomic analysis of M. purpureus YY-1 and winter was performed. Comparative transcriptomic analysis reveals pksCT, the essential gene for citrinin synthesis, showed low expression level in M. purpureus YY-1 and winter, which suggested there might be isoenzymes in M. purpureus YY-1 that were responsible for the citrinin synthesis during evolution. In addition, the expression change of transcription factors may also influence the regulatory network of citrinin synthesis pathway of in M. purpureus. Moreover, the yields of pigments produced by the winter mutant were significantly increased. Repressing central carbon metabolism and improving the acetyl-CoA pool can contribute to the high yield of pigments, and enhanced NADPH regeneration also lead the metabolic flux to pigments in M. purpureus. Investigations on biosynthesis and regulation of citrinin and pigment production in M purpureus will enhance our knowledge of the mechanisms in fungal secondary metabolite biosynthesis.
2018-05-02 | GSE107628 | GEO
Project description:Monascus is a filamentous fungus that is widely used for producing Monascus pigments in the food industry in Southeast Asia. While the development of bioinformatics has helped elucidate the molecular mechanism underlying metabolic engineering of secondary metabolite biosynthesis, the biological information on the metabolic engineering of the morphology of Monascus remains unclear. In this study, the whole genome of M. purpureus CSU-M183 strain was sequenced using combined single-molecule real-time DNA sequencing and next-generation sequencing platforms. The length of the genome assembly was 23.75 Mb in size with a GC content of 49.13%, 69 genomic contigs and encoded 7305 putative predicted genes. In addition, we identified the secondary metabolite biosynthetic gene clusters and the chitin synthesis pathway in the genome of the high pigment-producing M. purpureus CSU-M183 strain. Furthermore, it is shown that the expression levels of most Monascus pigment and citrinin clusters located genes were significantly enhanced via atmospheric room temperature plasma mutagenesis. The results provide a basis for understanding the secondary metabolite biosynthesis, and constructing the metabolic engineering of the morphology of Monascus.
| S-EPMC9159588 | biostudies-literature
Project description:To reduce the production cost of Monascus pigments (MPs), the utilization of rice bran (RB), an agricultural waste product, as a substrate in submerged fermentation was conducted in this study. To improve MP production, different nutritional ingredients including mannitol (Man), NH4NO3 (AN), ZnSO4 (Zn), and optimization (Opti), which was a synthesis of the three above ones, were added in rice bran (RB) medium. The yields of MPs, pigment constituents, and growth and development of Monascus purpureus M9 were investigated in this study. Man had the maximum color value of 3,532 U/g, which was 18.69 times more than that of RB and reached up to 76.65% of the value of rice (Rice) fermentation. Man significantly increased the production of two orange pigments, monascorubrin and rubropunctatin, of which the yields were 69.49 and 95.36% of the counterpart of Rice. The biomass and colony diameter of Opti presented the maximum value among different groups. AN and RB induced more asexual spore formation, whereas Opti and Man promoted sexual spore production. Comparative transcriptomic analysis showed that different nutritional ingredients led to changes in pigment production, promoting the growth and development of M. purpureus M9 through the regulation of related gene expression. Man and Opti improved MP production by regulating the primary metabolism, including the Embden-Meyerhof pathway (EMP), the pentose phosphate (PP) pathway, the tricarboxylic (TCA) cycle, fatty acid degradation (FAD), fatty acid biosynthesis (FAB), amino acid metabolism (AAM), and fructose and mannose metabolism (FMM), to provide the precursors (acetyl-CoA and malonyl-CoA) for MP biosynthesis. This study presents a low-cost method for increasing MP production and explains the molecular mechanisms of different nutritional ingredients for enhancing MP biosynthesis.
| S-EPMC10753769 | biostudies-literature
Project description:Amino acids could act as nitrogen sources, amido group donors, or bioactive molecules in fungi fermentation, and consequently, play important roles in Monascus pigments (MPs) biosynthesis. But the understanding of the effects of various amino acids on MPs biosynthesis is still incomprehensive. In this work, 20 free amino acids were added to the fermentation medium to evaluate their effects on MPs biosynthesis in Monascus purpureus RP2. Six amino acids, namely, histidine (HIS), lysine (LYS), tyrosine (TYR), phenylalanine (PHE), methionine (MET), and cysteine (CYS), were selected as the valuable ones as they exerted significant effects on the production yield and even on the biosynthesis metabolic curves of MPs. Moreover, the dose-dependent and synergistic effects of valuable amino acids on MPs biosynthesis were observed by tests of serial concentrations and different combinations. In addition, it revealed that HIS and MET were the prominent amino acids with dominant and universal influences on MPs biosynthesis. The analog compounds of HIS (amitrole) and MET [calcium 2-hydroxy-4-(methylthio)] were added to the fermentation medium, and the results further confirmed the extraordinary effects of HIS and MET and their analogs on MPs biosynthesis. Furthermore, the gene transcription profile indicated that a differential expression pattern was observed in the polyketide synthase (PKS) cluster responsible for MPs biosynthesis in response to HIS and MET, revealing that they could oppositely regulate MPs biosynthesis in different ways. These findings would benefit the understanding of MPs biosynthesis regulation mechanism in M. purpureus and contribute to the industrial production of MPs by fermentation.
| S-EPMC9335072 | biostudies-literature
Project description:Citrinin, a secondary fungal metabolite of polyketide origin, is moderately nephrotoxic to vertebrates, including humans. From the red-pigment producer Monascus purpureus, a 21-kbp region flanking pksCT, which encodes citrinin polyketide synthase, was cloned. Four open reading frames (ORFs) (orf1, orf2, orf3, and orf4) in the 5'-flanking region and one ORF (orf5) in the 3'-flanking region were identified in the vicinity of pksCT. orf1 to orf5 encode a homolog of a dehydrogenase (similarity, 46%), a regulator (similarity, 38%), an oxygenase (similarity, 41%), an oxidoreductase (similarity, 26%), and a transporter (similarity, 58%), respectively. orf2 (2,006 bp with four introns) encodes a 576-amino-acid protein containing a typical Zn(II)2Cys6 DNA binding motif at the N terminus and was designated ctnA. Although reverse transcriptase PCR analysis revealed that all of these ORFs, except for orf1, were transcribed with pksCT under citrinin production conditions, the disruption of ctnA caused large decreases in the transcription of pksCT and orf5, together with reduction of citrinin production to barely detectable levels, suggesting that these two genes are under control of the ctnA product. Complementation of the ctnA disruptant with intact ctnA on an autonomously replicating plasmid restored both transcription and citrinin production, indicating that CtnA is a major activator of citrinin biosynthesis.
| S-EPMC1950990 | biostudies-literature
Project description:Amino acid metabolism could exert regulatory effects on Monascus pigments (MPs) biosynthesis. In this work, MPs biosynthesis regulated by methionine and S-adenosylmethionine (SAM) was investigated in Monascus purpureus RP2. The results indicated that the addition of methionine in fermentation significantly reduced MPs production by 60-70%, and it induced a higher expression of SAM synthetase Mon2A2272 and consequently led to SAM accumulation. However, the addition of SAM in fermentation promoted MPs production by a maximum of 35%, while over-expression of the gene Mon2A2272 led to a decrease in MPs yield, suggesting that SAM synthetase and SAM were likely to play different regulatory roles in MPs biosynthesis. Furthermore, the gene transcription profile indicated that SAM synthetase expression led to a higher expression of the transcriptional regulatory protein of the MPs biosynthesis gene cluster, while the addition of SAM gave rise to a higher expression of MPs biosynthesis activator and the global regulator LaeA, which probably accounted for changes in MPs production and the mycelium colony morphology of M. purpureus RP2 triggered by methionine and SAM. This work proposed a possible regulation mechanism of MPs biosynthesis by SAM metabolism from methionine. The findings provided a new perspective for a deep understanding of MPs biosynthesis regulation in M. purpureus.
| S-EPMC9237499 | biostudies-literature