Assessment of zinc solubilization potential of zinc-resistant Pseudomonas oleovorans strain ZSB13 isolated from contaminated soil

Zinc is an essential micronutrient that is required for optimum plant growth. It is present in soil in insoluble forms. Bacterial solubilization of soil unavailable form of Zn into available form, is an emerging approach to alleviate the Zn deficiency for plants and human beings. Zinc solubilizing bacteria (ZSB) could be a substitute for chemical Zn fertilizer. The present study aimed to isolate and characterize bacterial species from the contaminated soil and evaluate their Zn solubilizing potential. Zn resistant bacteria were isolated and evaluated for their MIC against Zn. Among the 13 isolated bacterial strains ZSB13 showed maximum MIC value upto 30mM/L. The bacterial strain with the highest resistance against Zn was selected for further analysis. Molecular characterization of ZSB13 was performed by 16S rRNA gene amplification which confirmed it as Pseudomonas oleovorans. Zn solubilization was determined through plate assay and broth medium. Four insoluble salts (zinc oxide (ZnO), zinc carbonate (ZnCO3), zinc sulphite (ZnS) and zinc phosphate (Zn3(PO4)2) were used for solubilization assay. Our results shows 11 mm clear halo zone on agar plates amended with ZnO. Likewise, ZSB13 showed significant release of Zn in broth amended with ZnCO3 (17 and 16.8 ppm) and ZnO (18.2 ppm). Furthermore, Zn resistance genes czcD was also enriched in ZSB13. In our study, bacterial strain comprising Zn solubilization potential has been isolated that could be further used for the growth enhancement of crops.

Optimization of Propagation Medium for Enhanced Polyhydroxyalkanoate Production by Pseudomonas oleovorans

Polyhydroxyalkanoates (PHAs) represent a promising alternative to commercially used petroleum-based plastics. Pseudomonas oleovorans is a natural producer of medium-chain-length PHA (mcl-PHA) under cultivation conditions with nitrogen limitation and carbon excess. Two-step cultivation appears to be an efficient but more expensive method of PHA production. Therefore, the aim of this work was to prepare a minimal synthetic medium for maximum biomass yield and to optimize selected independent variables by response surface methodology (RSM). The highest biomass yield (1.71 ± 0.04 g/L) was achieved in the optimized medium containing 8.4 g/L glucose, 5.7 g/L sodium ammonium phosphate and 35.4 mM phosphate buffer. Under these conditions, both carbon and nitrogen sources were completely consumed after 48 h of the cultivation and the biomass yield was 1.7-fold higher than in the conventional medium recommended by the literature. This approach demonstrates the possibility of using two-stage PHA cultivation to obtain the maximum amount of biomass and PHA.

Polyhydroxyalkanoates (PHAs) Production from Volatile Fatty Acids (VFAs) from Organic Wastes by Pseudomonas oleovorans

This study aimed to investigate the production of polyhydroxyalkanoates (PHAs), a biodegradable polymer from organic wastes by Pseudomonas oleovorans. Volatile fatty acids (VFAs) from acidogenic fermentations of chicken manure (VFAs-CM) and potato peels (VFAs-PP), rich in organic matter majorly acetic (49.9%), butyric (15%) and propionic acids (11.1%) were utilized as substrates for microbial processes. During 72 h of cultivations, samples were withdrawn at intervals and analyzed for cell growth parameters, PHAs accumulation and polymeric properties. The highest biopolymer accumulation (0.39 g PHAs/g DCW) was achieved at 48 h of cultivation from medium containing VFAs-PP as the sole source of carbon. On characterization, the produced biopolymers were shown to be semi-crystalline of carbonyl C=O group. Additionally, thermogravimetric analysis (TGA) showed that the produced biopolymers demonstrated the capability to withstand thermal degradation above prescribed temperatures at which cross-linking isomerization reaction occurs, which is a vital property denoting the thermal stability of biopolymer.

Analysis of bacterial growth parttern in bioprocessing of polyhydroxyalkanoates from waste oil by Pseudomonas oleovorans

Pseudomonas oleovorans NCIMB 6576 and Ralstonia eutropha NCIMB 10442 were used for the production of Polyhydroxyalkanoates (PHA) from industrial waste cooking oils, the bacteria were cultured on tryptone soya broth (TSB) and Tryptone soya agar (TSA). The growth pattern of the bacteria, serial dilution and viable counting was done using the Miles and Misra method, 0.5ml (500 µl) of the sample was transferred aseptically into test tubes filled with 4.5ml ringer solution (1/4 strength) resulting in a ten-fold dilution, the growth curve of the cultures of P. oleovorans NCIMB6576 grown on TSB with and without PS oil sample shows error bars in the graph for each point depicting the standard error of the mean. The initial viable count ranges between 6.37 log10 cfu/ml and 5.1 log10 cfu/ml. The viable count reached its peak after 30 hours giving approximately 9.7 log10 cfu/ml for P. oleovorans NCIMB6576 with PS oil and 9.24 log10 cfu/ml after 30 hours as well without the oil, showing that maximum cell count was attained at the same time. The growth curves of P. oleovorans NCIMB6576 grown on TSB with and without the oil sample TS, where the errors bars depicts the standard errors of the means on each point. The initial viable count at the start of the experiments shows that for P. oleovorans NCIMB6576 grown with the oil, there was an initial viable count of 6.1 log10 cfu/ml as compared to 5.1 log10 cfu/ml without the oil respectively. It was observe that the time at which maximum cell counts was attained is slightly longer when the oil was not used as a carbon source (30 hours) as compared to the oil control (27 hours). A decline in cell count is also noticeable after 30 hours until it reaches its minimum value of 9.4 log.10 cfu/ml after 48 hours in the experiment involving the oil sample TS.

Polyhydroxyalkanoates (PHAs), bioprocessing using waste oil

Pseudomonas oleovorans NCIMB 6576 and Ralstonia eutropha NCIMB 10442 were used for the production of Polyhydroxyalkanoates (PHA) from industrial waste cooking oils, the bacteria were cultured on tryptone soya broth (TSB) and Tryptone soya agar (TSA). P. oleovorans NCIMB6576 gave a better percentage PHB yield (8.2%) with PS oil as carbon source as compared to 6.45% with TS oil. However, a very low yield (0.64%) was recorded when P. oleovorans NCIMB6576 was grown on TSB without the oils as carbon source. Ralstonia eutropha NCIMB 10442 gave an appreciable yield of 13.63% and 14.80% with PS and TS oil samples respectively as carbon source with negligible variation in the yields. The results obtained across all experiments were compared with one another. The SEM images from the PHB samples generated from the experiments shows that there is a slight difference in the surface morphologies of the PHB with respect to the oil samples as well as the different bacteria used in the experiment.

Study into biodegradation of cocamidopropyl betaine, an amphoteric surfactant, by Pseudomonas bacteria and activated sludge

The paper examines the biodegradation rate of cocamidopropyl betaine by bacteria of the genus Pseudomonas and activated sludge. The following microorganisms were taken as destructor strains: Pseudomonas fluorescens TR (VKPM B-4881), Pseudomonas putida TP-19 (B-6582), Pseudomonas stutzeri T (B-4904), Pseudomonas putida TSh-18 (B-2950), Pseudomonas putida TO (B-3959), Pseudomonas mendocina 2S (B-4710), Pseudomonas oleovorans TF4-1L (B-8621) and activated sludge obtained at activated sludge reactors of a Kuzbass plant. Biooxidation of surfactant samples was carried out in 250 cm3 glass flasks, placed into an incubator shaker, at a constant temperature of 30ºС for pure cultures and 18ºС for activated sludge. The destructor strain should reduce the surfactant concentration to safe values within a minimum time interval. Pseudomonas stutzeri T (B-4904) and Pseudomonas fluorescens TR (B-4881) strains provided the shortest half-life of the surfactant under study – 2.5 and 2.6 days, respectively. For Pseudomonas putida TO (B-3959), Pseudomonas putida TSh-18 (B-2950) and Pseudomonas oleovorans TF4-1L (B-8621) strains, these values amounted to 3.0, 4.5 and 4.9 days, respectively. The maximum half-life of the surfactant under study was demonstrated by Pseudomonas mendocina 2S (B-4710) and Pseudomonas putida TP-19 (B-6582) microorganisms – 5.5 and 6.0 days, respectively. The maximum biodegradation of the surfactant was observed under its exposure to the biocenosis of microorganisms. Over 14 days, the concentration of cocamidopropyl betaine decreased to 0.27% of its initial concentration. The efficiency of Pseudomonas bacteria as destructors of surfactants was demonstrated. Bacteria of this genus exhibit a shorter generation time and a higher rate of biomass growth when compared to other strains and a shorter period of adaptation to surfactants when compared to activated sludge. Capable of reducing surfactant concentrations to safe values in a minimum time interval, Pseudomonas strains can be used as an effective agent in the development of technologies for wastewater purification from amphoteric surfactants.

Complete Genome Sequences of Two Pseudomonas Species Isolated from Marine Environments of the Pacific Ocean

ABSTRACT Pseudomonas marincola YsY11 and Pseudomonas oleovorans T9AD were both isolated from marine environments of the Pacific Ocean. Here, we report the whole-genome sequences of these two organisms. Pseudomonas marincola YsY11 consists of a single 4.77-Mb chromosome, and Pseudomonas oleovorans T9AD consists of a 5.57-Mb chromosome and a 2.8-kb plasmid.