| Monascus spp.,a kind of fungus used in food production and traditional medicine for thousands of years in China,has become an important microorganism resources due to its yield of many kinds of metabolites,such as hongqu pigment,monacolins,γ-aminobutyric acid(GABA),ergosterol,which are used as food fermentation starter,food colorant, function food and raw materials of medicine.At present,the investigation about Monascus spp.was focused on its classification,breeding,metabolites isolation and fermentation conditions to improve useful metabolites,but the study on molecular biology of Monascus spp.is at the beginning stage.It was found that most of the sequences related to Monascus spp.in Genbank were carried on classification and identification of the homology,few was functional genes.Up to now,it has no report about the gene(s) involved in hongqu function.UV mutation was used to produce mutants of M-7 in my study.24 mutants including petite colony and albino mutant were obtained.Our study mainly included analysis on colony morphology,micro-morphology and yield of secondary metabolites,which established theoretical foundation and produced basic materials to explore functional gene.The main research contents are as follows.1.Monascus tuber M-7 UV mutagenesisAfter slant culture of M-7 for 18 d,spores were washed by sterile water,separated by beads,diluted to 10~6 ind/mL and plastered on 25 cm×30 cm petri dishe.Some mutants of different morphology were selected by UV mutagenesis and were cultured in the conditions of avoiding light.Had got 26 mutants which changed in configuration.After three generations,I had got 24 mutant stable.The steady transmissibility is 92.3%.These mutants were named 501c,518b,518e,618a,618f,618e,618h,1102a,729b,929b,929h, 929j,1102g,929k,729c,501d,929d,929f,929g,421a,421c,426q,618g,1102b。2.The mutants' colony morphology characteristicCultivated M-7 and other mutants on PDA for 9 d,classified these mutants by their clony characteristic.Being divided into five group:the mutants similar with M-7,7 strains in all,they were 1102a,729b,929b,929h,929j,1102g,929k;the petite colony mutants,7 strains in all,they were 501c,518b,518e,618a,618f,618e,618h;the Albino mutant,only one strain,it was 729c;the villiform clony mutants,4 strains,they were 501d,929d,929f,929g;the castaneous clony mutants,they were 421a,421c,426q,618g, 1102b.And then cultivated these mutants 15 d,observed these mutants under microscope. 3.Secondary metabolites analysis of mutants and original strain M-7Extracted monacolin k,GABA,citrinin,pigment from the RFR made by these strains.The result was:501d produced the highest yield of monacolin k,390.77μg/g,618f, 929h,929b,929j produced little monacolin k,the yield was lower than the detect limit; 618h produced the highest yield of citrinin,40.12μg/g,the yield of 729c,421a and 421c was lower than the detect limit;518b produced GABA most,798.25μg/g,421a produced the least,20.07μg/g;618h produced the highest yield pigment,2457 u/g,729c produced the least,37 u/g.4.Preliminary study of fermentation on mutants 501d and 618hIn order to research the characteristics of these mutants better,we have done fermentation research on 618h and 501d.Include solid-state fermentation and liquid-state fermentation.The result is:(1)Solid-state fermentation.At 30℃,mutants produce citrinin the highest;at 25℃,monacolin k production arrived the highest yield.From 15～35℃,the pigment-value increased gradually,but from 30℃,the trendance of increase turned slowly. From 8 d～15 d,the yield monacolin k,GABA,citrinin,pigment-value all incrised gradually,and then,all the production reduced.(2) Liquid-state fermentation.Took glycerin as carbon source,the yield of monacolin k,GABA,citrinin,pigment-value were higher than others.Took glucose as carbon source,the yield of citrinin was lower. Different pH of culture medium infected the yield of metabolites much.When the value of pH was 3,they produced all the metabolites little.When the value of pH was 5,the yield of monacolin k and pigment was the highest.When the value of pH was 6,the yield of citrinin was the highest.
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