Research Of Hypotensive Substances Produced By Monascus Spp.

γ-Aminobutyric acid(GABA) is an Hypotensive substance. The main contents of this thesis were: to screen Monascus spp. and lactic acid bacteria strains producing GABA highly; to optimize the fermentation cultivation processes of Monascus spp. and lactic acid bacteria; to study the characters of Monascus spp. Glutamate decarboxylase(GAD); to discuss the coculture of Monascus spp. and lactic acid bacteria.The method of HPLC-ELSD analyzing GABA was studied, and confirmed the optimal chromatography conditions.Monascus pilosus GM016 and lactic acid bacteria 5 producing GABA were screened, and their characters were reseached. The optimal temperature and pH of Monascus pilosus GM016 were 30℃and 5.0, and could endure 14% (V/V) ethanol. Lactic acid bacteria 5^# reacted with catalase, and it didn't produce H₂, so it was a feminine reaction; it reacted with arginine and didn't produce NH₃; it could be fermented by lactose, galactose, maltose, sucrose and glucose, and it couldn't be fermented by ribose and xylose. So lactic acid bacteria 5^# was primarily identified to be Lactobacillus acidophilus. The liquid fermentation process of Monascus pilosus GM016 and lactic acid bacteria 5^# were optimized. The optimal cultivation condition of Monascus pilosus GM016 was: rice power 5%, glucose 7%, soybean power 1.0%, yeast power 1.5%, L-Glu 0.8%, NaNO₃ 0.5%, KH₂PO₄ 0.15%, MgSO₄-7H₂O 0.1%, CaCl₂ 0.15%, VB₆ 0.15%, pH4.2, seed age 40 hours, 10% inoculum, 100ml/500ml (v/v) encased fermentation liquid volume, 30℃, 180r/min, cultivated for 12 days, and in this condition the content of GABA was 0.395g/L. The optimal cultivation condition of lactic acid bacteria 5^# was: peptone 0.5%, yeast extract 0.5%, lactose 1.0%, L-Glu 1.0%, pH7.0, 4% inoculum, 150ml/250ml (v/v) encased fermentation liquid volume, 33℃, cultivated for 48 hours, and in this condition the content of GABA was over 0.46g/L.The characters of Glutamate decarboxylase(GAD) from Monascus pilosus GM016 were studied. The optimal temperature of GAD was 30℃, and about 30℃it was steady. The optimal pH of GAD was 4.5, and the GAD ability between pH 4.5 to pH 5.5 was high and steady.The coculture mode of Monascus pilosus GM016 and lactic acid ba- cteria 5^# was discussed, Monascus pilosus GM016 inoculum was put into lactic acid bacteria 5^# by fermented for 3 days, and then cocultured for 12 days. The content of GABA was to 0.60g/L.