Studies On The Genetic Diversity Comparation And Fermentation Characteristics Of 41 Monascus Strains

Monascus is a very important fungus in industrial production, which has been applied for thousand of years in our country. It can be made into many kinds of traditional food by fermentation, such as red yeast rice, red kojic rice wine, red fermented bean curd and so on. Modern research showed that Monascus can produce a variety of metabolites and many are very useful in food, medicine and chemical industry, which has an important value and a good prospect for application. Therefore, the research for Monscus has the vital significance.In this study, we obtained 41 Monascus strains and made a classification and identification for them after separation and purification. And we made a research of germplasm resources for those strains using RAPD and ISSR marker, which revealed the genetic diversity and showed ISSR molecular markers was more stable and better in repeatability than RAPD markers. Then we measured the ability of producing amylase, pigments, and monacolin K in those Monascus strains after fermentation to evaluate the strain characterictics.Taking identification of 41 Monascus strains from various regions as materials, we constructed the phylogenetic tree based on the analysis of ITS (Internal Transcribed Spacer) by software MEGA5.10 to combine colonial morphology characteristics with physiology biochemical experiment. The ITS sequence length of those strains were around 520 bp, GC content was ranged from 56.2% to 58.0%, and the average genetic distance of those 41 various sequences was 0.0052. To be combined with morphology characteristics and physiology biochemical experiment, the 41 Monascus strains were classed into six categories which were M.purpureus, M.pilosus, M.aurantiacus, M.ruber, M.fumeus and M.albidulus by the analysis of molecule biology.The research evaluated the applicability of RAPD (random amplified polymorphic DNA) and ISSR (Inter-simple sequence repeat) molecular markers analysis on the genetic diversity and geographical variation of Monascus, which aimed to make a foundation for genetic diversity study of Monascus. In the study, RAPD and ISSR markers were applied for genetic diversity analysis of 41 Monascus strains from various regions of Fujian Province, China. ISSR amplification reactions used 7 screened primers. Fifty-six polymorphic bands were produced with 93.33% polymorphic ratio by ISSR analysis, and the genetic similarity coefficients (GSC) of strains were ranged from 0.50 to 1.00. The comparative sequence analysis used 7 screened RAPD primers to amplify a total forty-nine polymorphic bands with 81.67% ratio, the GSC by RAPD analysis were 0.62-1.00. Correlation analysis revealed a significant positive correlation for genetic distance between RAPD and ISSR markers by SPSS 17.0 software, which indicated that those 2 markers were both suitable for genetic diversity analysis of Monascus. However, ISSR molecular markers was more suitable for being used in classification and determination of Monascus, and RAPD for analysis of the differences among different strains in a same Monascus species. According to the analysis results of two kinds of markers, Monascus had rich genetic diversity, and the genetic relationship ofmonascus strains had a certain correlation with their geographic source by clustering analysis of UPGMA method on software NTSYSpc-2.10e.We researched the ability of these strains to produce metabolites by liquid and solid state fermentation method, including the ability of producing amylase, pigments, and monacolin K, so that it can lay a foundation for better application of Monascus in various fields. Compared the pigment production capacity, Monascus purpureus, Monascus aurantiacus and Monascus rubber were better than Monascus pilosus, Monascus fumeus and Monascus albidulus; compared with Monascus aurantiacus and Monascus ruber, Monascus purpureus was better at high-producing pigment and each pigment compoment; and the ability of Monascus pilosus was the worst of these six species. Compared amylase-producing capacity, Monascus purpureus and Monascus aurantiacus had a relatively higher level of producing that enzyme, and there were difference in the amylase production capacity of different strains within a same species. In the comparative analysis of monacolin K-producing capability, only some strains of the spicies Monascus pilosus produced it, other species all did not. It showed that Monascus pilosus was unique in these six species to produce monacolin K, and there were difference in capacity of producing monacolin K of different strains within Monascus pilosus. In consequence, the fermentation characteristics of different Monascus species were dissimilar, even the characteristics of the different strains within a same species were still variant.