Immobilization and Ammonia Removal of Photosynthetic Bacteria

2012 ◽  
Vol 610-613 ◽  
pp. 311-314 ◽  
Author(s):  
Pei Rong Zhan ◽  
Wei Liu
Keyword(s):  
Electron Microscopy ◽  
Amino Acids ◽  
Photosynthetic Bacteria ◽  
Rhodopseudomonas Palustris ◽  
Carbon Sources ◽  
Water Environment ◽  
Photosynthetic Bacterium ◽  
Ammonia Removal ◽  
Fish Pond ◽  
Immobilized Microorganisms

The photosynthetic bacteria have been widely used in improving the water environment, especially for pollutant purification. A photosynthetic bacterium was isolated from fish pond sludge using various methods. The bacterium is rod-shaped and slightly curved, and they reproduce by budding. It grew anaerobically when exposed to light and aerobically in darkness. Based on electron microscopy, utilization of carbon sources and amino acids, and factors required for growth, the bacterium is identified as Rhodopseudomonas palustris. The R. palustris was immobilized using different carriers to increase its concentration and its targeted use. The results show that immobilization of the bacteria stabilized the ammonia removal and protected the bacteria from predation by plankton. The method is also easy to use and prolonged the purification effect in the reactor. The immobilized microorganisms are 30%–40% more effective than free bacteria in removing ammonia.

scholarly journals Investigating and modelling the effect of light intensity on Rhodopseudomonas palustris growth

2021 ◽  
Author(s):  
Brandon Ross ◽  
Robert William McClelland Pott
Keyword(s):  
Experimental Data ◽  
Light Intensity ◽  
Photosynthetic Bacteria ◽  
Rhodopseudomonas Palustris ◽  
Photosynthetic Bacterium ◽  
Light Penetration ◽  
Tubular Photobioreactor ◽  
Photobioreactor Design ◽  
High Purity Hydrogen ◽  
Effect Of Light

Photosynthetic bacteria can be useful biotechnological tools – they produce a variety of valuable products, including high purity hydrogen, and can simultaneously treat recalcitrant wastewaters. However, while photobioreactors have been designed and modelled for photosynthetic algae and cyanobacteria, there has been less work on understanding the effect of light in photosynthetic bacterial fermentations. In order to design photobioreactors, and processes using these organisms, robust models of light penetration, utilisation and conversion are needed. This article uses experimental data from a tubular photobioreactor designed to focus in on light intensity effects, to model the effect of light intensity on the growth of Rhodopseudomonas palustris, a model photosynthetic bacterium. The work demonstrates that growth is controlled by light intensity, and that this organism does experience photoinhibition above 600 W/m2, which has implications for outdoor applications. Further, the work presents a model for light penetration in circular photobioreactors, which tends to be the most common geometry. The work extends the modelling tools for these organisms, and will allow for better photobioreactor design, and the integration of modelling tools in designing processes which use photosynthetic bacteria.

scholarly journals Redirection of Metabolism for Biological Hydrogen Production

2007 ◽  
Vol 73 (5) ◽  
pp. 1665-1671 ◽  
Author(s):  
Federico E. Rey ◽  
Erin K. Heiniger ◽  
Caroline S. Harwood
Keyword(s):  
Nitrogen Fixation ◽  
Hydrogen Production ◽  
Photosynthetic Bacteria ◽  
Rhodopseudomonas Palustris ◽  
Photosynthetic Bacterium ◽  
Selection Strategy ◽  
Wild Type ◽  
Purple Photosynthetic Bacteria ◽  
Mutant Strains ◽  
Different Strains

ABSTRACT A major route for hydrogen production by purple photosynthetic bacteria is biological nitrogen fixation. Nitrogenases reduce atmospheric nitrogen to ammonia with the concomitant obligate production of molecular hydrogen. However, hydrogen production in the context of nitrogen fixation is a rather inefficient process because about 75% of the reductant consumed by the nitrogenase is used to generate ammonia. In this study we describe a selection strategy to isolate strains of purple photosynthetic bacteria in which hydrogen production is necessary for growth and independent of nitrogen fixation. We obtained four mutant strains of the photosynthetic bacterium Rhodopseudomonas palustris that produce hydrogen constitutively, even in the presence of ammonium, a condition where wild-type cells do not accumulate detectable amounts of hydrogen. Some of these strains produced up to five times more hydrogen than did wild-type cells growing under nitrogen-fixing conditions. Transcriptome analyses of the hydrogen-producing mutant strains revealed that in addition to the nitrogenase genes, 18 other genes are potentially required to produce hydrogen. The mutations that caused constitutive hydrogen production mapped to four different sites in the NifA transcriptional regulator in the four different strains. The strategy presented here can be applied to the large number of diverse species of anoxygenic photosynthetic bacteria that are known to exist in nature to identify strains for which there are fitness incentives to produce hydrogen.

Directive Effect of Chain Length in Modulating Peptide Nano-assemblies

2020 ◽  
Vol 27 (9) ◽  
pp. 923-929
Author(s):  
Gaurav Pandey ◽  
Prem Prakash Das ◽  
Vibin Ramakrishnan
Keyword(s):  
Electron Microscopy ◽  
Amino Acids ◽  
Light Scattering ◽  
Chain Length ◽  
Self Assembly ◽  
The Self ◽  
Ionic Charge ◽  
Self Assembling ◽  
Biophysical Techniques

Background: RADA-4 (Ac-RADARADARADARADA-NH2) is the most extensively studied and marketed self-assembling peptide, forming hydrogel, used to create defined threedimensional microenvironments for cell culture applications. Objectives: In this work, we use various biophysical techniques to investigate the length dependency of RADA aggregation and assembly. Methods: We synthesized a series of RADA-N peptides, N ranging from 1 to 4, resulting in four peptides having 4, 8, 12, and 16 amino acids in their sequence. Through a combination of various biophysical methods including thioflavin T fluorescence assay, static right angle light scattering assay, Dynamic Light Scattering (DLS), electron microscopy, CD, and IR spectroscopy, we have examined the role of chain-length on the self-assembly of RADA peptide. Results: Our observations show that the aggregation of ionic, charge-complementary RADA motifcontaining peptides is length-dependent, with N less than 3 are not forming spontaneous selfassemblies. Conclusion: The six biophysical experiments discussed in this paper validate the significance of chain-length on the epitaxial growth of RADA peptide self-assembly.

Effects of algae, yeast and photosynthetic bacteria diets on survival and growth performance in the fairy shrimp, Streptocephalus sirindhornae (Branchiopoda, Anostraca)

Crustaceana ◽  
2018 ◽  
Vol 91 (12) ◽  
pp. 1505-1522 ◽  
Author(s):  
Chewapat Saejung ◽  
Anuwat Chaiyarat ◽  
La-Orsri Sanoamuang
Keyword(s):  
Growth Performance ◽  
Photosynthetic Bacteria ◽  
Photosynthetic Bacterium ◽  
Ammonia Concentration ◽  
Fairy Shrimp ◽  
Shrimp Culture ◽  
Survival And Growth ◽  
Nitrate And Nitrite ◽  
First Time

Abstract This study investigated the effects on survival, growth performance and water quality of algae, yeast and photosynthetic bacteria as diets for larval and immature/mature Streptocephalus sirindhornae. Survival of the larvae fed with the alga Chlorella vulgaris and the photosynthetic bacterium Rhodopseudomonas faecalis for 5 days was higher than 80%, while those fed with the yeast Saccharomyces cerevisiae was 4.4%. After feeding the 6-day-old fairy shrimp until they reached 30 days of age, those fed with bacteria showed the highest survival and growth rate. Ammonia, nitrate and nitrite concentrations in the water treated with R. faecalis were the lowest. The highest ammonia concentration, the lowest dissolved oxygen, and excessive turbidity were found in the yeast treatment. Frequent water replacement could not overcome this, which resulted in the low survival rate. Utilization of photosynthetic bacteria in fairy shrimp culture is for the first time reported herein, and the disadvantages of using yeast in S. sirindhornae cultivation are discussed.

scholarly journals Transcriptomic Analysis of Staphylococcus xylosus in Solid Dairy Matrix Reveals an Aerobic Lifestyle Adapted to Rind

2020 ◽  
Vol 8 (11) ◽  
pp. 1807
Author(s):  
Sabine Leroy ◽  
Sergine Even ◽  
Pierre Micheau ◽  
Anne de La Foye ◽  
Valérie Laroute ◽  
...  
Keyword(s):  
Gene Expression ◽  
Amino Acids ◽  
Antioxidant Enzymes ◽  
Dairy Products ◽  
Molecular Mechanisms ◽  
Iron Acquisition ◽  
Carbon Sources ◽  
Original System ◽  
Staphylococcus Xylosus ◽  
Genes Encoding

Staphylococcus xylosus is found in the microbiota of traditional cheeses, particularly in the rind of soft smeared cheeses. Despite its frequency, the molecular mechanisms allowing the growth and adaptation of S. xylosus in dairy products are still poorly understood. A transcriptomic approach was used to determine how the gene expression profile is modified during the fermentation step in a solid dairy matrix. S. xylosus developed an aerobic metabolism perfectly suited to the cheese rind. It overexpressed genes involved in the aerobic catabolism of two carbon sources in the dairy matrix, lactose and citrate. Interestingly, S. xylosus must cope with nutritional shortage such as amino acids, peptides, and nucleotides, consequently, an extensive up-regulation of genes involved in their biosynthesis was observed. As expected, the gene sigB was overexpressed in relation with general stress and entry into the stationary phase and several genes under its regulation, such as those involved in transport of anions, cations and in pigmentation were up-regulated. Up-regulation of genes encoding antioxidant enzymes and glycine betaine transport and synthesis systems showed that S. xylosus has to cope with oxidative and osmotic stresses. S. xylosus expressed an original system potentially involved in iron acquisition from lactoferrin.

scholarly journals The effects of Rhodopseudomonas palustris PSB06 and CGA009 with different agricultural applications on rice growth and rhizosphere bacterial communities

AMB Express ◽  
2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Luyun Luo ◽  
Pei Wang ◽  
Zhongying Zhai ◽  
Pin Su ◽  
Xinqiu Tan ◽  
...  
Keyword(s):  
Treatment Group ◽  
Bacterial Communities ◽  
Photosynthetic Bacteria ◽  
Rhodopseudomonas Palustris ◽  
Rice Seedling ◽  
Seedling Stage ◽  
Rice Rhizosphere ◽  
Rice Growth ◽  
Agricultural Applications ◽  
Rhizosphere Bacterial Communities

Abstract In recent years, the photosynthetic bacteria have been used widely in agriculture, but the effects of different agricultural applications on crop rhizosphere microorganism and crops are lack. In this study, we provide new insights into the structure and composition of the rice root-associated microbiomes as well as the effect on crop of the Rhodopseudomonas palustris(R. palustris) PSB06 and CGA009 at the rice seedling stage with seed immersion and root irrigation. Compare with CK group, the length of stem, the peroxidase (POD), and superoxide dismutase (SOD) activities in PSB06 treatment group was significantly higher, while the length of stem in CGA009 treatment group was significantly higher. The POD and SOD activities in CGA009 treatment groups only were higher slightly than the CK group. In the study, the dominant phyla were Proteobacteria (51.95–61.66%), Bacteroidetes (5.40–9.39%), Acidobacteria (4.50–10.52%), Actinobacteria (5.06–8.14%), Planctomycetes (2.90–4.48%), Chloroflexi (2.23–5.06%) and Firmicutes (2.38–7.30%), accounted for 87% bacterial sequences. The principal coordinate analysis (pCoA) and mantel results showed the two application actions of R. palustris CGA009 and PSB06 had significant effects on rice rhizosphere bacterial communities (p < 0.05). The PSB06 can significantly promote the rice growth and enhance stress resistance of rice at the seedling stage, while the R. palustris CGA009 has no significant effect on rice. Dissimilarity test and canonical correspondence analysis (CCA) results showed that the TN and pH were the key factors affecting rice rhizosphere bacterial community in the seedling stage. This study will provide some guidance advices for the study of the microecological regulation of photosynthetic bacteria on crops.

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