title: Single-cell protein production from Jerusalem artichoke extract by a recently isolated marine yeast Cryptococcus aureus G7a and its nutritive analysis.
abstract: After crude protein of the marine yeast strains maintained in this laboratory was estimated by the method of Kjehldahl, we found that the G7a strain which was identified to be a strain of Cryptococcus aureus according to the routine identification and molecular methods contained high level of protein and could grow on a wide range of carbon sources. The optimal medium for single-cell protein production was seawater containing 6.0 g of wet weight of Jerusalem artichoke extract per 100 ml of medium and 4.0 g of the hydrolysate of soybean meal per 100 ml of medium, while the optimal conditions for single-cell protein production were pH 5.0 and 28.0 degrees C. After fermentation for 56 h, 10.1 g of cell dry weight per liter of medium and 53.0 g of crude protein per 100 g of cell dry weight (5.4 g/l of medium) were achieved, leaving 0.05 g of reducing sugar per 100 ml of medium and 0.072 g of total sugar per 100 ml of medium total sugar in the fermented medium. The yeast strain only contained 2.1 g of nucleic acid per 100 g of cell dry weight, but its cells contained a large amount of C(16:0) (19.0%), C(18:0) (46.3%), and C(18:1) (33.3%) fatty acids and had a large amount of essential amino acids, especially lysine (12.6%) and leucine (9.1%), and vitamin C (2.2 mg per 100 g of cell dry weight). These results show that the new marine yeast strain was suitable for single-cell protein production.
authors.affiliation: UNESCO Chinese Center of Marine Biotechnology, Ocean University of China, Yushan Road, No. 5, Qingdao, China.
authors.forename: Lingmei
authors.initials: L
authors.lastname: Gao
authors.forename: Zhenming
authors.initials: Z
authors.lastname: Chi
authors.forename: Jun
authors.initials: J
authors.lastname: Sheng
authors.forename: Xiumei
authors.initials: X
authors.lastname: Ni
authors.forename: Lin
authors.initials: L
authors.lastname: Wang
mesh_terms: D003454:Cryptococcus / Q000201:enzymology* / Q000254:growth & development / Q000302:isolation & purification; D003470:Culture Media / Q000737:chemistry*; D004044:Dietary Proteins; D006368:Helianthus / Q000378:metabolism*; D007444:Inulin / Q000378:metabolism*; D012623:Seawater
chemical_list: D003470:Culture Media; D004044:Dietary Proteins; C012551:single cell proteins; D007444:Inulin