| Monascus pigment as a kind of traditional natural pigments are widely used in the field of food colorants. Monascus can produce orange and yellow pigment, red pigment has achieved a large-scale industrial production, but for Monascus pigment formation mechanism is still in the initial stage of research. With mixed fungus culture and liquid fermentation method, this research aiming at monascus pigment, under the condition of mixed fungus cultivation and ammonium, we researching on the effects of Monascus pigment metabolized.To promote Monascus yellow pigment generated, four microorganisms and Monascus mixed culture to research the role of the pigment-producing. Liquid fermentation test explore Monascus pigment synthesis mechanism by choosing Aspergillus Niger; Under the condition of ammonium restriction, the pigment color value, pigment promoting rate, caproic acid content and octylic acid content were detected, and through the SWATH technology resolving differences in protein. The main results were as follows:(1) The mixed fungus culture results showed that Aspergillus Niger on Monascus orange and yellow pigment are known as a strong role, the intracellular orange colour and yellow pigment promoting rate reached 97.07% and 50.00%, respectively. Escherichia coli and Bacillus natto had a significant effect on metabolism of Monascus, the closer vaccination distance, the higher the amount of metabolized red pigment.(2) Useing liquid fermentation, aiming at Monascus yellow pigment, the preliminary discussion on the influence of Aspergillus Niger on Monascus pigment synthesis with the liquid fermentation of Monascus and Aspergillus Niger. Inoculating with 0.8% Aspergillus Niger in Monascus fermentation for 36 h, the Monascus pigment promoting rate is higher. Aspergillus Niger itself affected Monascus’s morphology and the enzyme may be the main reason for the red pigment-producing was initially identified.(3) Under the condition of the ammonium, the study found that Monascus at the pre-fermentation Monascus (0-24 h) and post-fermentation (72-120 h) will use a lot of ammonium. Ammonium content decreased in the late fermentation (72 h-144 h) has generated a lot of pigment. The control group was higher than the amount of pigment-producing ammonium salt group is due to the pigment-producing precursor fatty acids limit. Meanwhile, the control group in the pre-fermentation (0-48 h) have a lot of caproic acid and octanoic acid, its content reached 41.97mg/L and 40.85mg/L, respectively. These two fatty acids will be utilized to generate the corresponding Monascus pigment in post-fermentation resulting in content decreased.Caproic acid and octanoic acid concentrations are low in ammonium salt group, and its highest concentrations are 31.39mg/L and 26.05mg/L, resectively.Thus the volume of corresponding Monascus pigment is lower than control group.(4) It found that differences in protein mainly involved in the metabolic process, cell communication and metabolic process by using the SWATH quantitative proteomic technology and GO enrichment analysis. Test successful quantified acetyl-coa carboxylase, alpha subunit fatty acid synthase, aldehyde dehydrogenase and some glycolytic enzyme, and found that ammonium groups in the protein expression level was significant different from the control group. The different proteins main impact in glycolytic pathway, citric acid cycle, fatty acid metabolic pathways, it results in the protein expression of control glycolytic pathway and TCA cycle up regulation under the conditions of ammonium salt, the protein of control synthesis of fatty acid and metabolic pathway down regulation. |
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