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 beta2 from Spirulina fusiformis exhibits plasmid DNA pBR322 scission prevention and cellular antioxidant activity.

Isolation of three different active peptides from C-phycocyanin (C-pc) beta chain of S. fusiformis and their biological properties are reported. Phycocyanin peptide beta fraction 2 (cyanopeptide beta 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 beta 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 beta2 in human fibroblast cell line TIG 3-20. In vitro cell scratch injury assay demonstrated the capacity of cyanopeptide beta2 in cell migration in to wounded area suggesting fibroblast proliferation and migration. The results suggest that cyanopeptide beta2 can be a free radical scavenger and effective peptide for future biomedical applications like wound healing, atherosclerosis, cell redox potential and hypoxia.

Tryptophan inhibits bacteriorhodopsin formation in Halorubrum sodomense A01.

Bacteriorhodopsin (bR) is well recognized for its applied values. We observed that the bottleneck associated with the use of different peptones for bR production was linked to the presence of tryptophan (Trp). Trp at 0.36 mM in the culture medium inhibits bR formation. The results obtained in this study demonstrate that bR content (mg l(-1)) of Halorubrum sodomense A01 decreased to 2.9 mg l(-1) in 0.36 mM Trp compared to control (0.11 mM Trp) where 12.3 mg l(-1) of bR was obtained. Our results provide useful information for the design of production conditions for bR to be used in applied settings.

Production and partial characterization of cellulase free xylanase by Bacillus subtilis C 01 using agriresidues and its application in biobleaching of nonwoody plant pulps.

AIMS: To optimize the solid-state cultivation conditions for xylanase production using agriresidues and testing the biobleaching efficiency of xylanase on nonwoody plant fibre materials. METHODS AND RESULTS: An extracellular cellulase free xylanase was produced from Bacillus subtilis C 01 using various inexpensive substrates under solid-state cultivation. High level of xylanase production (135 IU gds(-1)) was observed when grown on wheat bran followed by maize powder (50 IU gds(-1)). The maximum xylanase (136 IU gds(-1)) production was occurred in wheat bran-to-moisture ratio of 1 : 1 at 72 h. The xylanase pretreated pulp samples of banana, silk cotton and cotton showed an increased brightness of 19.6, 11.6 and 7.9%, respectively. CONCLUSIONS: The enzyme-aided biobleaching results indicate that the xylanase has potential application in enhancing the brightness of nonwoody plant fibre pulp. SIGNIFICANCE AND IMPACT OF THE STUDY: This is the first report on biobleaching of banana fibres, silk cotton and cotton pulps using xylanase. The biobleaching results of secondary fibres are promising and can be transferred to paper mills, which utilize nonwoody plant fibres as a raw material for paper production.

Biobleaching of banana fibre pulp using Bacillus subtilis C O1 xylanase produced from wheat bran under solid-state cultivation.

A cellulase-free xylanase produced by Bacillus subtilis C 01 from wheat bran under solid-state cultivation was tested for its efficacy in biobleaching of raw banana fibre and banana pulp obtained through a mechanical pulping process. Banana pulp samples treated with crude xylanase (450 nkat g(-1) pulp) resulted in a 19.6% increase in the brightness as compared to untreated pulp. The presence of chromophores, hydrophobic compounds and an increased reducing sugar (10.79 mg g(-1) pulp) quantity in the bleached solution after enzymatic treatment indicated the removal of materials that were absorbed at 237 nm from the banana pulp.

Pigment production in Spirulina fussiformis in different photophysical conditions.

The present investigation makes a comparative investigation of individual light source on the different commercially important pigments in Spirulina fussiformis in photobioreactor culture condition. Continuous culture system was carried out throughout the experimental condition. Initially, seed culture, corresponding to 0.2 g/L on dry weight basis was cultivated in Zarrouks medium with different colored light source in reactor. Maximum daily biomass productivity, 0.8 g/L, 0.75 g/L and 0.69 g/L in white light (WL), blue light (BL) and green light (GL), respectively, conditions was noticed. Pigment content during WL treatment showed the highest accumulation (5.5 microg/mL) of chlorophyll whereas, other pigments roughly remained constant without much change, implying WL intensity is better for chlorophyll synthesis. On the other hand, chlorophyll and phycocyanin content gradually increased up to 7 microg/mL and 2 mg/mL, respectively, at BL intensity. The response to GL was negative to all pigments studied except for phycocyanin; in this case a highest production (2.5 mg/mL) was seen during 18 days experimental period. Additionally, when yellow light (YL) treatment experiments were conducted, the rate of production gradually decreased from 6th day onward in all pigments demonstrating the photobleaching effect of YL. The average rate of pigments production did not show significant accumulation in red light (RL) light treatment except phycoerythrin which showed an increasing trend of production. It is worth to mention here that higher light intensity is better for production of phycocyanin and phycoerythrin in Spirulina.

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.

Erythrocytes sedimentation profiles under gravitational field as determined by He-Ne laser. II. Influence of erythrocyte shape.

The erythrocyte sedimentation profiles under gravitational field, by scanning the sample holder along the height and width, containing the blood samples with normal and crenated erythrocytes, are determined. The normal shape of erythrocytes has been altered by the controlled He-Ne laser exposures and this change, as observed microscopically, is similar to that as produced by other methods. At low exposure the erythrocytes have normal appearance, whereas, at 400 mJ/cm2, the percentage of crenated cells is 25 +/- 5 percent. It is observed that the modification of the shape influences the sedimentation characteristics of the erythrocytes. The erythrocytes tend to move faster after being exposed to lower exposure and slower after being exposed to higher exposure compared to that of normal erythrocytes. The possible mechanism associated with this change is discussed.

Changes in shape of erythrocytes in rabbits on atherogenic diet and onion extracts.

The effects of administration of cholesterol alone and of cholesterol and fresh whole onion extract, on the shape of erythrocytes, were studied in albino rabbits. In animals on a cholesterol-enriched diet, the erythrocytes changed shape and showed an increased tendency to aggregate, whereas they retained their normal appearance in animals on cholesterol and onion extract, and did not differ from those of normal control rabbits.

Effects of onion in induced atherosclerosis in rabbits: I. Reduction of arterial lesions and lipid levels.

The effects of dietary cholesterol alone and of cholesterol in combination with fresh whole onion extract on the lesions and aortic lipid concentrations were studied in albino rabbits. The lesions produced were significantly greater in cholesterol-fed animals. In animals given the cholesterol diet, the aortic cholesterol levels were significantly greater than in the onion extract and cholesterol-fed animals. The aortic total lipid levels in latter group were comparable to the levels of control group.