ABSTRACT
Microbial transformation technology has been applied in the study of Chinese materia medica (CMM) widely. Photosynthetic bacteria biotransformation in the research of Chinese medicine pharmaceutics has become one of the focuses in the field of microbial transformation technology. In this paper, we summarized the pharmacological activity and pharmacodynamic material bases of CMM metabolized by photosynthetic bacteria, in addition, summarized the mechanism of photosynthetic bacteria biotransformation. We also pointed out the problems needed to be studied in the future.
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Two purple nonsulfur bacteria (PNSB) strains, Rhodobium marinum NW16 and Rhodobacter sphaeroides KMS24 were investigated for their potential to remove heavy metals (HMs) from contaminated shrimp pond water. Tolerance of both PNSB strains growing with both microaerobic-light and aerobic-dark conditions, based on their minimum inhibitory concentrations, was in the order of Cu2+ > Zn2+ > Cd2+ (Pb precipitation occurred at 0.34 mM). Results from a scanning electron microscope equipped with an energy dispersive X-ray spectrometer (SEM-EDX) indicated that Cu2+ and Zn2+ altered the cellular morphology of both strains and accumulated HMs were found in their cells. The highest amounts of both cations were found in their cell walls followed by the cytoplasm and cell membrane. Using the highest concentrations (mM) of HMs found in shrimp pond of 0.0067 Cd2+, 0.54 Cu2+, 0.30 Pb2+, 0.89 Zn2+ and 3 percent NaCl under both incubating conditions exopolymeric substances (EPS) produced by both strains showed a greater removal of all HMs (average percentages; 90.52-97.29) than their cells (average percentages; 14.02-75.03).
Subject(s)
Aquaculture , Bacteria , Environmental Pollution , Metals, Heavy/metabolism , Polymers/metabolism , Biodegradation, Environmental , Decapoda , Microbial Sensitivity Tests , Rhodobacter sphaeroidesABSTRACT
The influence factors for hydrogen production using photosynthetic bacteria group were studied. The effects of carbon sources, nitrogen sources, carbon concentration, nitrogen concentration, initial pH value, illumination mode and inoculation amount on hydrogen production were investigated by experiment of single factor and orthogonal experiment. The optimum process conditions were as follows: the best bacteria group was number 3, the glucose was carbon source and concentration of carbon source was 3 g/L; the urea was nitrogen source and concentration of nitrogen source was 9 g/L; the inoculation amount was 10%; initial pH value was 8.5; the illumination mode was 12 h light and 12 h dark alternation; incubation temperature was 30?C. The main factors affecting hydrogen production were strain, carbon sources, carbon source concentration and nitrogen suorces.
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The growth characteristics of hydrogen-production photosynthetic bacterial biofilm in a plate-type biofilm bioreactor were studied experimentally.The effect of hydraulic and nutritional conditions on the surface coverage,thickness,dry weight,and density of Rhodoseudomonas palustris biofilm was observed,respectively.Glucose in the influent concentration range from 0.05 to 10 g/L was used as the sole carbon source.Liquid flow rate was varied from 37.8 to 1080ml/h in the experiments.Experimental results showed that the hydraulic and nutritional conditions had significant influences on the growth rate and structure of biofilm.In a lower flow rate range,high liquid flow rate was propitious to the diffusion of substrate from liquid phase to solid-liquid interface,which resulted in the fast development of biofilm on the solid-liquid interface.However,some parts of biofilm were scraped off when the flow rate exceeded a threshold.At a fixed liquid flow rate,the biofilm density increased with the increase in the substrate concentration.The biofilm having thick and loose structure was developed under low substrate concentration condition.The biofilm structure was convenient for the nutrient transfer in the biofilm,which is a survival strategy of microorganisms facing adverse circumstances.
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The effect of initial substrate concentration on the growth,metabolic activities of Photosynthetic bacteria (PSB) in the process of hydrogen production is studied.The empirical relation of the initial substrate concentration to the specific growth rate,specific substrate consumption rate and specific hydrogen production rate of PSB are developed based on the modified Monod model.It is found that the results given by the model are well agreed with the experimental data in growth phase and stationary phase of PSB.Meanwhile,the optimal substrate concentration in the process of growth,metabolism and hydrogen production is 50 mmol/L.Furthermore,when the initial substrate concentration deviates 50 mmol/L,the activation of PSB is limited or inhibited,and the inhibiting effect is more prominent than the limiting effect.In addition,it is demonstrated that initial substrate concentration has little effect on the specific substrate consumption rate.
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Objective: To study the effect of photosynthetic bacteria (PSB) on serum lipids and antioxidant capacity. Methods: The rabbits were fed high lipid diet to induce hyperlipidemia. The effect of PSB on hyperlipidemia was studied with Spirulina platensis as the positive control. The content of serum TC, TG , HDL-C, SOD activity, and the content of GSH, LPO were determined. Results: PSB could significantly reduce the content of TC,TG , LDL-C in serum, increase H/L and decrease AI ratio. Meanwhile, PSB could improve antioxidant capacity, as greatly increase blood SOD activity, GSH in blood and liver, and reduce serum LPO. In comparison, PSB was better than Spirulina platensis. Conclusion: PSB can significantly regulate lipid metabolism and improve antioxidant capacity in hyperlipidemic rabbits.
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Objective: To study the prevention and treatment of photosynthetic bacteria (PSB) on atherosclerosis (AS). Method: The hypolipidemic effect of PSB on atherosclerosis (AS) in rabbits induced by high cholesterol diet was studied with Spirulina platensis as positive control. The content of liver TC,AS plaque area percentage (PA) and the emphraxis of coronary artery were determined. Results:PSB could significantly reduce the content of TC in liver, the liver index (LW/BW), and PA 63.99%, 21.96%, 70.10%, respectively, and remarkably abate the lipid aggregation in liver and the pathological changes of coronary artery. In comparison,PSB was better than Spirulina platensis. Conclusion:PSB can prevent the formation of atherosclerosis in hyperlipidemic rabbits.
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Numerous prokaryotes, belonging to physiologically and taxonomically different groups, are able to produce hydrogen. Some photosynthetic bacteria have the property of light-dependent production of hydrogen from organic substrates. We isolated several photosynthetic purple and green bacteria from enrichment cultures made from the water of a waste-water pond of a cool-drink refilling station. After testing them for their ability to use various organic compounds as carbon source, and sulphide, thiosulphate and organic compounds as electron donor, we selected the fastest-growing isolate, a Rhodopseudomonas, for a study of its ability to produce molecular hydrogen in presence of light. Immobilized cells of this isolate produced significant amounts of hydrogen from both sewage and waste water.
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Objective To screen and identify photosynthetic bacteria that could be used to treat bean wastewater. Methods Photosynthetic bacteria (PSB) were screened by enrichment culture from the sludge. The morphological and biochemical characteristics of the bacteria were determined using transmission electron microscope, live cells'scanning and testing of utilization of different carbon sources. In addition, the sequence of 16S rRNA of the PSB was analysed and the homology was compared with the standard strain according to the sequence in the GenBank. Results A strain NS-04 was screened from the sludge of the pond in Nanjing. The bacteria was Gram-negative in shape of ovoid or rod, with size of 0.6-0.9 ?m wide and 1.2-2.0 ?m long. The multiplication manner of the bacteria was binary fission. The photosynthetic membrane was lamellar type, which was under and parallel to intro-cytoplasmic membrane. The clone was brown with major pigments riched in carotenoids and bacteriochlorophylla. The bacteria could grow both under anaerobic condition in the light and aerobic condition in the dark. The bacteria could utilize many kinds of carbon sources and the growth of the cells could be prompted by yeast extract. The analysis of phylogenetic tree of 16S rRNA sequence indicated that the similarity of strain NS-04 and the standard strain of Rhodopseudomonas palustris in GenBank was 97%. Conclusion According to Bergey's Manual of Systematic Bacteriology, strain NS-04 was identified to be Rhodopseudomonas palustris.