Novel substrate (algal protein) for cultivation of Rhodospirillum rubrum.

Rhodospirillum rubrum was grown under light anaerobic conditions with phycocyanin (C-pc) extracted from Spirulina platensis as the sole source of carbon and nitrogen. When grown under these conditions cellular components like lipids, carbohydrates, protein, carotenoids, bacteriochlorophyll were similar to the one grown with malic acid and ammonium chloride. Growth of R. rubrum increased with increase in concentration of C-pc (200 to 1000 mg/l). R. rubrum also utilized C-pc under dark anaerobic condition. With both malic acid and C-pc as carbon sources C-pc was consumed only after exhaustion of malic acid under light anaerobic condition. No aberration of cell morphology was seen under scanning electron microscope (SEM). R. rubrum utilized both phycocyanobilin and phycoprotein individually as well as in combination. When grown with 1000 mg/l of phycoprotein 450 mg/l of biomass was obtained, and with combination of phycocyanobilin (75 mg/l) and phycoprotein (925 mg/l) 610 mg/l of biomass was obtained. Phycocyanobilin alone did not inhibit the growth of R. rubrum. Utilization of C-pc with protease like activity was observed in plate assay. Protease like activity was also observed as zones around the colonies in plates containing sterilized casein, gelatin and filter sterilized bovine serum albumin. No amino acids were detected in the supernatant when analyzed with ninhydrin. Extracellular protease like activity was highest when C-pc was used as substrate (2.8 U/ml). Intracellular protease like activity was not detected in cell free extracts.

Cysteine rich cyanopeptide β2 from Spirulina fussiformis exhibits plasmid DNA pBR322 scission prevention and cellular antioxidant activity.

Isolation of three different active peptides from C-phycocyanin (C-pc) β chain of S. fussiformis and their biological properties are reported. Phycocyanin peptide β fraction 2 (cyanopeptide β 2) facilitated both antioxidant and plasmid DNA strand scission prevention activity due to higher cysteine moieties in the isolated peptide. The peptide significantly scavenged the free radicals like 1-1,-diphenyl-2-picryl hydrazyl and ferric reducing ability of plasma, increased the absorbance values in reducing power and also showed the higher trolox equivalent antioxidant capacity values in total reactive antioxidant potentials assay. Cyanopeptide β 2 also inhibited reactive oxygen species induced DNA pBR322 damage in dose dependent manner along with free radical scavenging properties suggesting the role in the DNA integrity which is also evident by DNA binding activity of peptide. In addition, the generation of reactive oxygen species (ROS) was dose dependent (10 and 20 ng/ml) and significantly quenched by cyanopeptide β2 in human fibroblast cell line TIG 3-20. In vitro cell scratch injury assay demonstrated the capacity of cyanopeptide β2 in cell migration in to wounded area suggesting fibroblast proliferation and migration. The results suggest that cyanopeptide β2 can be a free radical scavenger and effective peptide for future biomedical applications like wound healing, atherosclerosis, cell redox potential and hypoxia.

Hydrogen production from glucose by Citrobacter freundii.

C. freundii, a member of Enterobacteriaceae was isolated from nearby sewage and characterised. With optimum conditions, its hydrogen production capacity and efficiency was tested in synthetic medium containing glucose as carbon and energy source. C. freundii was grown in a 51 fermentor under batch anaerobic conditions. The total production of gas was 8.91 in the volumetric ratio of 63% H2 and 37% CO2 in 11 hr from 30.8 g glucose. From 1 mole of glucose 1.286 mole of hydrogen was produced (YH2/s). The rate of gas production (rQ) and hydrogen production (rH2) was 0.71 and 0.45 1/hr respectively. The strain appears to be a better one for hydrogen production compared to the earlier Citrobacter spp reported.