Study On Isolation Of Marine Bacteria And Selection Of Fermentation Conditions For Producing Chito-Amino-Oligosaccharides

In this paper,adopting selective culture medium and brilliant clear circle were used to enrich and screen for marine bacteria strains producing chito-amino-oligosaccharides from the samples.12 strains were isolated.A strain with high chito-amino-oligosaccharides producing ability designated HB003 was chosen for studying its physiogical properties.It showed that the colony of HB003 is circular,moist and pale yellow in color,no spore,mobile by single polar flagellum,facultative anaerobic.It is Gram-negative.Its 16s rDNA sequence is highly similar with Vibrio Genus.The optimal initial pH for growth is 8～8.5 and the temperature is 25℃～30℃.It has NaCl resistance.153.5 mg/L chito-amino-oligosaccharides can be produced by fermentation of HB003 in initial pH 8.5 and 30℃chitin culture media for 6 days.The effects of compositions of culture medium and cultural conditions on chito-amino-oligosaccharids production were investigated.The optimal culture medium are: chitin 10 g,Peptone 5 g,MgSO₄·7H₂O 0.6 g,FeSO₄ 0.01 g,K₂HPO₄ 0.9 g, KH₂PO₄ 0.6 g,NaCl 20 g,H₂O 1000 mL,pH 8.0;The optimal cultural conditions including fermentation temperature,rotation rate and amount of inoculation are:30℃,120 rpm,and 1%,respectively.The yield of chito-amino-oligosaccharides can be improved to 703.5 mg/L.