Isolation, partial characterization, and biological properties of polysaccharides from crude papain

Optimization, production and characterization of glycolipid biosurfactant from the marine actinobacterium, Streptomyces sp. MAB36

A potential glycolipid biosurfactant producer Streptomyces sp. MAB36 was isolated from marine sediment samples. Medium composition and culture conditions for the glycolipid biosurfactant production by Streptomyces sp. MAB36 were optimized, using two statistical methods: Plackett-Burman design was applied to find out the key ingredients and conditions for the best yield of glycolipid biosurfactant production and central composite design was used to optimize the concentration of the four significant variables, starch, casein, crude oil and incubation time. Fructose and yeast extract were the best carbon and nitrogen sources for the production of the glycolipid biosurfactant. Biochemical characterizations including FTIR and MS studies suggested the glycolipid nature of the biosurfactant. The isolated glycolipid biosurfactant reduced the surface tension of water from 73.2 to 32.4 mN/m. The purified glycolipid biosurfactant showed critical micelle concentrations of 36 mg/l. The glycolipid biosurfactant was effective at very low concentrations over a wide range of temperature, pH, and NaCl concentration. The purified glycolipid biosurfactant showed strong antimicrobial activity. Thus, the strain Streptomyces sp. MAB36 has proved to be a potential source of glycolipid biosurfactant that could be used for the bioremediation processes in the marine environment.

Structural analysis of papaya polysaccharide II

The structure of papaya polysaccharide II (PP II) isolated by Chandrasekaran et al. [Carbohydr. Res., 60 (1978) 105-115] has been investigated by methylation analysis of the carboxyl-reduced polymer and by partial hydrolysis of both the intact (arabinose, 31.0; rhamnose, 13.3; galactose, 42.6; glucuronic acid, 10.3; and 4-O-methylglucuronic acid, 2.8%), and carboxyl-reduced polymers. Methylation analysis of carboxyl-reduced PP II indicated a very highly branched structure in which approximately 39% of the galactopyranose units are disubstituted, 24% are monosubstituted, 20% are trisubstituted, and 17% are nonreducing end units. Methylation analysis of products of partial hydrolysis of both intact and carboxyl-reduced polymers indicated that the backbone of the polysaccharide is made up of galactosyl residues substituted at either O-3 or -6, that the principal aldobiouronic acid fragment is 6-O-(glucopyranosyluronic acid)galactose, that the rhamnosyl units are substituted at O-3 with either terminal arabinofuranosyl or galactopyranosyl groups, and that the rhamnosyl residues are themselves linked to glucuronic acid residues through O-4. From this information, a possible statistical fragment with six arabinofuranose and two galactopyranose nonreducing end-groups per 19 sugar units [five units in the main chain of (1----3)-linked galactopyranose units] is proposed.