Potential Of Bacterial Isolates Research Articles

Exploring the styrene metabolism by aerobic bacterial isolates for the effective management of leachates in an aqueous system

In the present study, the styrene metabolic profile of three aerobic bacterial isolates explored in a batch mode study. The isolates found application in the management of elachates in the waste dump yard. These three bacterial species have different origins and were studied as a single and mixed consortia. The Lysinibacillus strain M01 (from marine sources), Lysinibacillus strain WD03 (from a waste dump yard), and Pseudomonas strain BG07 (from bovine gut) were used in the present study. The styrene concentration was fixed in the range between 0.5 and 1.5 mL L−1. The metabolites obtained upon microbial degradation were assessed using high-performance liquid chromatography (HPLC), UV-visible spectroscopy, and FTIR spectroscopy (Fourier transform infrared spectroscopy). Furthermore, the genes (Sty A, B, C, D, and E) responsible for the degradation of styrene by the three abovementioned isolates were identified using PCR with respective designed primers. Instrumental analyses revealed the presence of phenylacetic acid (PAA) at significant levels in the growth medium after the scheduled experimental period and confirmed the metabolism of styrene by the chosen isolates. Compared to the case of individual cultures, the results of the mixed consortia support the metabolism of styrene at appreciable levels. The present study provides a suitable biological solution for the management of leachates containing styrene and a way to achieve industrially important chemicals (PAA) through a microbially mediated process.

Pseudomonas montielli-A Potent Chemotherapeutic Asparaginase producing organism Isolated from Rhizosphere Soil

The enzyme Asparaginase finds its extensive application in chemotherapeutic as well as in food manufacturing industries on a large scale. Prolonged use of the enzyme from a single source can lead to hypersensitive reactions and hence there is a continual need in isolating asparaginase from various microorganisms with lesser toxicity and side effects. The present study was attempted to isolate a potential bacterial isolate with higher yield and less cytotoxic activity. Rhizosphere soil bacteria were isolated on a minimal medium M9 with 1% L-asparagine. Pink coloured zone producing isolates were selected and identified using standard biochemical tests. The organisms isolated include Klebsiella sp, Pseudomonas sp and Staphylococcus sp. Extraction of the enzyme was done after submerged fermentation in M9 medium and was quantified by nesslerization method. The isolate showing maximum activity was further screened for its cytotoxicity property on vero cell line to prove its safety. The isolate was further characterized by 16S rRNA analysis and was identified as Pseudomonas montielli which could be a novel organism producing asparaginase.

ISOLASI DAN UJI ANTAGONIS MIKROORGANISME LOKAL (MOL) REBUNG BAMBU TERHADAP CENDAWAN Fusarium sp

Efforts to increase the production of chilli plants are still experiencing obstacles. One of the diseases caused by fungi is fusarium wilt disease caused by Fusarium sp. The existence of this fungus attack makes one of the limiting factors that cause a decrease in red chili production. Local microorganism (MOL) solution is a fermented solution made from various local available resources. MOL solution contains micro and macro nutrients and also contains bacteria that have the potential to remodel organic matter, stimulate growth, and as a controlling agent for pests and plant diseases, so that MOL can be used both as a decomposer, biological fertilizer and as an organic pesticide, especially as a fungicide.In this research, bacterial isolation from MOL bamboo shoots will be carried out and then tested the isolates on Fusarium sp. The data of this research were analyzed descriptive. The results of isolation from bamboo shoot MOL which has been fermented for use as POC, obtained 8 bacterial isolates with different macroscopic and microscopic characteristics. All obtained bacterial isolates have the potential to inhibit the growth of fusarium fungal colonies. The most potential bacterial isolate was M6 isolate with a diameter of a pathogenic fungal colony that grew only by 2.1 cm.Keywords: Fusarium sp., Local Microorganisms, Bamboo Shoots

Decoding multifarious role of cow dung bacteria in mobilization of zinc fractions along with growth promotion of C. annuum L.

Zinc is one of the micronutrients, required by all types of crops. About 10–100ppm of zinc is present in soil which is generally immobile. The cow dung sustains all life and being practice since aeons. Exploitation of cow dung bacteria can mobilize nutrients besides contributing in sustainable agriculture. Therefore, to examine mobilization of Zn, cow dung is used as a source of bacteria. The objectives of the present study were to isolate an array of bacteria from cow dung and to characterize them for their Zn (ZnO and ZnCO3) mobilization ability in addition to establish the optimum conditions for dissolution of zinc. A total of seventy bacterial isolates have been screened for Zn mobilization. Out of which most potent (CDK15 and CDK25) were selected to study the effect of various parameters viz. pH, temperature and concentration of Zn. These parameters were assessed qualitatively in diverse growth medium and quantitatively using Atomic absorption spectroscopy. Optimum pH and temperature for mobilization was recorded at pH 5 (ZnO) and 37 °C (ZnCO3) by CDK25, whereas, optimum zinc concentration for mobilization was recorded at 0.05% (ZnO) by CDK15. Maximum amount of Zn solubilized was recorded by CDK25 in ZnO (20ppm). Considering the abilities of most potent bacterial isolates with reference to P-mobilization and growth promoting traits, pot culture assay of C. annuum L. was carried out. The findings of which conclude that, bacterium CDK25 (Bacillus megaterium) could be exploited for factors viz. nutrient management of Zn, growth promoting agent, and Zn augmentation in soil.

Cellulase induction enzymes characteristics of hindguts of endemic termites of North Sulawesi

The necessity for enzyme utilization in various industrial applications and reducing production cost for a more economical process compelled this research to seek for an alternative source of endemic enzyme for various sources cellulotic enzymes. The termites hindgut is known as a fermentor chamber of its own containing bacterial isolates with the potential to induce cellulosic substrates. Series of research have been conducted to obtain cellulolytic potential bacterial isolates characterized biochemically and molecularly. The purpose of this research was to determine the enzyme characters of cellulolytic bacterial from the hindguts of endemic termites of North Sulawesi. Screening results from various bacterial isolates from hindguts of local termites of several regencies from North Sulawesi identified Bacillus cereus from the hindgut of Odontotermes javanicus from South Minahasa (North Sulawesi). This Bacillus cereus isolate had the best cellulolytic potential by exhibiting a cellulolytic index of 1.75 cm on a selective media of CMC, with the best enzyme production on the 6th day with the activity of 0.0054U/ml.

Mitigation of drought stress in wheat crop by drought tolerant endophytic bacterial isolates

Bacteria with potential to alleviate abiotic stresses in combination with plant growth promotion are extremely useful in sustainable agriculture. The present study involves the isolation and evaluation of 14 bacterial isolates obtained from four upland rice roots in varying concentrations of PEG-6000. Three potential isolates MKA2, MKA3 and MKA4 were selected for further experiments. A pot experiment was conducted with four treatments under well watered and drought conditions. Water deficit treatment was imposed by reducing the amount of water added to 25% of the field capacity. Twenty days post stress results showed that drought stress affected the physiological and biochemical parameters of uninoculated wheat seedlings. Inoculation with the three bacterial isolates diluted the adverse effects of drought on relative water content and membrane stability index, and thus improved the water use efficiency over the uninoculated control. Inoculation also improved the shoot and root biomass of wheat plants in comparison to uninoculated control treatment under drought stress. Increased levels of super oxide dismutase and catalase activities were observed in treated plants as compared to control plants thus protecting the plants from oxidative damage. Thus, these potent bacterial isolates could be used effectively to ameliorate plant water intake efficiency and improve sustainability in wheat crop under drought conditions.

Carbon Dioxide Sequestering Ability of Bacterial Carbonic Anhydrase in a Mangrove Soil Microcosm and Its Bio-mineralization Properties

In this study, we attempt to prospect potential bacterial isolates from mangrove sediments of Mangalavanam, Kerala, India, with positive carbonic anhydrase (CA) activity to sequester carbon dioxide by calcium precipitation process. Fifteen bacterial colonies (M1–M15) isolated were screened for their carbonic anhydrase enzyme production potential based on p-nitro phenol acetate assay. Based on the secondary screening, M3 and M8 were identified as the most potential for carbonic anhydrase production. The specific activity of the partially purified CA enzyme from M3 and M8 were 44 U mg−1 and 76 U mg−1 respectively. The enzyme activity increased by 1.6-fold upon precipitation by acetone (80%). The potential isolate which higher CA production, M8 was identified as Bacillus altitudinis based on 16S rDNA sequencing. Soil microcosm was established to study carbonic anhydrase production and CO2 sequestration ability of B. altitudinis M8 strain. B. altitudinis M8 strain could reduce CO2 by 75 ± 0.12% in microcosm composed of sterilized soil with bacteria (SSB) and by 97 ± 0.34% in microcosm with sterile soil with enzyme (SSE). Hence, the application of enzyme was found to be more effective in removing CO2 when compared to bacterial inoculum. To further understand the bio-mineralization ability of this microbial isolate, calcium precipitation assay was conducted. There was a reduction of 42.22 ± 0.23% of free calcium in the medium through calcite precipitation. The carbonic anhydrase-mediated calcium precipitation by B. altitudinis M8 strain could be effectively employed in the process of carbon dioxide sequestration.

Assessment of the Petroleum Oil Degradation Capacity of Indigenous Bacterial Species Isolated from Petroleum Oil-Contaminated Soil

Petroleum hydrocarbons are highly toxic to plants, animals, and humans and are carcinogenic effects to plants, animals, and humans. The present study is focused to enhance the degradation of petroleum hydrocarbons using potential indigenous bacterial isolates. Bacteria were isolated from different petroleum oil-contaminated sites and characterized. Bacterial growth was evaluated under different physico-chemical parameters. The petroleum hydrocarbon degradation potentiality was assessed using GC–MS analysis. Forty-nine bacterial isolates were screened; only three isolates (ALK-14, ALK-16, and ALK-23) have good potential to degrade petroleum hydrocarbons and were identified as Alcaligenes species ALK-14, Bacillus methylotrophicus ALK-16, and Enterobacter species ALK-23, respectively, on the basis of morphology, biochemical characterization, and 16S rRNA sequencing. Optimum growth of Alcaligenes species ALK-14, Bacillus methylotrophicus ALK-16, and Enterobacter species ALK-23 occurred at pH 7, 6, and 6, respectively. Petroleum oil concentration found suitable for growth of selected bacterial isolates Alcaligenes species ALK-14, Bacillus methylotrophicus ALK-16, and Enterobacter species ALK-23 were 4%, 8%, and 4% (v/v), respectively. Among different nitrogen sources, ammonium nitrate was found suitable source for the maximum growth of Alcaligenes species ALK-14, Bacillus methylotrophicus ALK-16 at the concentration of 0.15 and 0.2%, respectively, and sodium nitrate for Enterobacter species ALK-23 at the concentration of 0.2%. All bacterial isolates showed maximum growth at 30 °C temperature. Synergistic effect on the growth of bacterial isolates under favourable conditions increased up to 11–28%. GC–MS analysis indicated that the hydrocarbon compounds in the range of C20–C44 were present in petrol. Maximum hydrocarbon degradation by Alcaligenes species ALK-14, Bacillus methylotrophicus ALK-16, and Enterobacter species ALK-23 was 11.65%, 8.11%, and 5.59%, respectively. The degradation of docosane 11-decyl, hexatriacontane, and eicosane by Alcaligenes species ALK-14 was 100%, 60%, and 48.8%, respectively. The degradation of docosane 11-decyl by, Bacillus methylotrophicus ALK-16, was 80%. Degradation of hexatriacontane by Enterobacter species ALK-23 was 31%. Further understanding of the metabolic processes of these organisms on crude oil hydrocarbons degradation will increase possibilities to develop strategies for removing crude oil pollutants from oil-impacted environments.

Multiple metal tolerance of Paenibacillus dentritiformis isolated from metal contaminated soils west Godavari district (Andhra Pradesh)

Sugar industrial effluents possess high amounts of toxic pollutants and contaminate the receiving sites. Treatment of contaminated sites by using microorganisms provides an alternate to conventional methods hence demands in the identification of metal tolerant microorganisms has been increasing day by day. Therefore in this study soil samples collected from Tanuku sugar factory residual effluent point (bank of Gosthani river), west Godavari district A.P were analyzed for the bacterial tolerance to Copper (Cu), Zinc (Zn) and Lead (Pb) in their chloride forms. Additionally, the study was carried out to identify the metal tolerant bacteria by morphological, biochemical and 16S rRNA gene sequencing studies. Four potential bacterial isolates were selected to analyze metal tolerance against CuCl2, ZnCl2, and PbCl2. The sequences were compared with those in NCBI and submitted in gene bank with accession numbers MK100333 (Paenibacillus cookie), MK100334 (Bacillus cereus), MK100335 (Aneurini bacillus sp) and MK100387 (Paenibacillus sp.). A Phylogenetic tree was constructed to Paenibacillus sp. the highly efficient bacterial strain among the four isolates using MEGA 7 soft ware. The results of this study showed that P. dentritiformis had multiple metal tolerances (Cu, Zn and Pb) up to 500mg/L after 72 hrs. The identified bacterial strain proved to be the strong heavy metal tolerant bacterial strain. Hence, its usage will be helpful in the treatment of heavy metals specifically Cu, Zn and Pb contaminated soils and further optimization of these cultures is required to improve its metal resistant capacity.

Potensi Antibakteri Isolat Bakteri Endofit dari Tanaman Purwoceng (Pimpinella pruatjan Molk.) Terhadap Klebsiella pneumoniae dan Salmonella typhi

Penelitian ini bertujuan untuk mengetahui isolat bakteri endofit purwoceng sebagai antibakteri. Pengujian antibakteri dilakukan dengan menggunakan metode difusi sumuran. Isolat bakteri endofit potensial terlebih dahulu diinokulasi ke dalam media fermentasi cair selama 52 jam dan selanjutnya dilakukan proses ekstraksi menggunakan pelarut n-Heksan. Ekstrak kasar ini digunakan untuk pengujian antibakteri terhadap K. pneumoniae dan S. typhi. Aktivitas antibakteri isolat bakteri endofit menggunakan media MHA (Mueller Hinton Agar) dengan ketebalan 6 mm dan ukuran diameter sumuran 5 mm. Hasil penelitian menunjukkan bahwa isolat bakteri endofit tanaman purwoceng tidak dapat menghambat pertumbuhan K. pneumoniae dan S. typhi.

The Probiotic Production of Konsorsium Bacteria of Sea Invertebrata for Biofilter as An Alternative Clean Water for Community

Sample of sea cucumbers, Holothuria atra and Holothuria scabra taken from the waters of the panjang island, Jepara. The purpose of this study is to determine whether the bacteria symbiont on the contents of the sea cucumber potential as a probiotic for biofilter in wastewater. Waste samples were collected from the water waste location in Semarang city which was high in population density, that is Tambak Lorok area. The study included: symbional bacterial isolation, symbionary bacterial screening as potential anti-pathogenic bacteria Staphylococcus aureus and Eschericia coli , amylolytic and proteolytic enzymatic tests, identified active bacterial species by Vitex test, a wastewater quality test of 100 mL mixed with consortium bacteria with concentration of 10 mL, then stand for 4 days. Further observations include: Phosphate levels, Nitrate content, pH, water odour, watercolour. The results showed that 24 isolates were isolated from Holothuria atra and Holothuria scabra species. It was found that there is only one type of potential isolate as anti bacterial pathogen Staphylococcus aureus . There are 4 bacteria that have enzyme activity. The results of identification with the Vitex method showed potential bacterial isolates: Sphingoonas paucimobilis. Water quality test results show that the scented water becomes odourless after given the consortium symbiotic of sea cucumber. The results concluded that the bacteria consortium of the contents of the intestines of Sea Cucumber potency as wastewater biofilter.

Selection of Phylloplane and Endophyte Microbes as Biocontrol for Rubber Leaf Fall Disease (Corynespora cassiicola)

<p><em>Leaf fall disease in rubber caused by </em>Corynespora cassiicola<em> </em><em>fungi significantly decreases rubber productivity. </em>C. cassiicola<em> causes leaves to fall all year round</em><em>, a delay in the tapping of immature rubber plants, yield decrease of producing plants, and even death of susceptible clones. The study aimed to obtain phylloplane and endophytic microbes potentially to inhibit the disease, was conducted from January to December 2016. The study used randomized complete design to assess antagonistic fungi and phylloplane and endophytic bacterias toward </em>C. cassiicola<em> in isolates obtained through exploration in </em><em>West Java and West Kalimantan. Pathogen isolation showed </em>Corynespora sp<em> with pale brown color, single conidia which slightly bended, shaped like a stick that is swollen at the base, with 2–14 septa. Inhibitory analysis found 42 fungi isolates and 19 bacteria isolates potentially inhibiting </em>C. cassiicola<em>. </em><em>Six fungi isolates have an inhibitory ability of ≥90%, consisting of two phylloplane fungi isolates (DTJF11 and CPSR7) and four endophytic fungi (CEBPM15, CEBPM23, CEBPM27, and CEPR9) with lysis, mycoparasitism, competition, and antibiosis inhibitory mechanism. The identification showed fungi isolate of DTJF11 is classified as </em>Trichoderma asperellum<em>, CPSR7 as </em>Talaromyces pinophilus<em>, and CEBPM15</em><em> as </em>Amanita tenuifolia<em>. </em><em>Potential bacterial isolates as biological agents are BP7, L3, BP3, BP4, BP5 and BP6 isolates, which have inhibitory power of 28.54%–40.94%, with antibiosis inhibition mechanism.</em></p>

Exploring Planococcus sp. TRC1, a bacterial isolate, for carotenoid pigment production and detoxification of paper mill effluent in immobilized fluidized bed reactor

Pulp and paper industry is one of the high priority sectors that generates large amount of solid (sludge) and liquid (paper mill effluent) wastes. Making use of this huge quantity of paper mill sludge (PMS) in an environment friendly manner is challenging and cost involving. Similarly the present wastewater treatment strategies based on physical and chemical methods encounter certain serious setbacks including secondary pollution generation with expensive mode of abatement processes. The present study aims at a “waste treats waste” strategy for the bioremediation of paper mill effluent in fluidized bed reactor (FBR) using another waste of the same industry, PMS as immobilizing matrix for Planococcus sp. TRC1, a wastewater bacterial isolate. This study simultaneously explores this isolate for the yellowish orange pigment it produces (2.3 ± 0.2 mg/gm of dry bacterial biomass) and characterizes it as a member of the pharmacologically important carotenoid pigment family via UV-Vis spectrophotometry, TLC, FT-IR and 13C NMR. The antioxidant potential of this pigment was studied by DPPH assay (IC50 = 33 ± 0.4 μg/ml) and H2O2 assay (IC50 = 147.4 ± 2.2 μg/ml). In FBR, the PMS immobilized bacteria showed removal of phenol, lignin, colour and COD from the effluent by 96%, 74%, 81% and 85% respectively after 60hr of treatment. The experimental data on immobilization fitted well with pseudo second-order (R2 = 0.955) and Freundlich adsorption isotherm (R2 = 0.996) models. The alterations in PMS before and after bacterial immobilization, as revealed by SEM and FT-IR, depicted the success of PMS as immobilization matrix. Phytotoxicity (90% seed germination) and mutagenicity studies confirmed that the treated effluent was substantially less toxic than its raw state. This study highlights a novel utilization possibility of PMS in an eco-friendly and economic way as immobilization matrix for Planococcus sp.TRC1 for paper pulp mill effluent treatment along with production of carotenoid pigment from this potential bacterial isolate as value added product.

Isolation, Identification and Partial Optimization of Novel Xylanolytic Bacterial Isolates from Bhilai-Durg Region, Chhattisgarh, India.

BackgroundPlant biomass and agricultural waste products disposal is a serious problem in agriculture based countries. These wastes, usually rich in xylan can be satisfactorily converted to industrially important and useful products by efficient biotechnological application of potent xylanase producing bacteria which generally have high temperature and pH optima.ObjectiveThe aim was to isolate and identify xylanolytic bacterial isolates from Bhilai-Durg region of Chhattisgarh, India which was otherwise unexplored for isolation of thermoalkalophilic xylanase producing bacteria. Partial scale up of process development was performed.Materials and MethodsXyalanse producing bacteria were isolated from probable samples following three stages of screening procedures. The potent isolates were identified and various parameters affecting xylanase production were optimized using the conventional one-factor-at-a-time approach.ResultsTwo potent indigenous bacterial isolates belonged to genus Bacillus and designated as Bacillus sp. MCC2728 and Bacillus sp. MCC2727 were isolated from forest soils with the ability to degrade xylan. Significant differences were observed in their morphology and phenotypic characters amongst themselves and with its closest type strains implying the novelty of the two isolates. After optimization, maximum xylanase levels were obtained at pH 9.0, 55 °C for Bacillus sp. MCC2728 and 50 °C for Bacillus sp. MCC2727, 5% inoculum, agitation speed (150 rpm). Yeast extract and peptone are best nitrogen sources and wheat bran, the best carbon source. The GenBank/EMBL/DDBJ accession numbers of strains Bacillus sp. MCC2728 and Bacillus sp. MCC2727 are KP742971 and KT444621 respectively. Wheat bran, Yeast extract and peptone proved to be the best carbon and nitrogen sources respectively and xylose as an additive was found to be contributing to maximize the xylanase yields.ConclusionTwo potent thermoalkalophilic novel bacterial isolates were successfully isolated with xylan degrading ability which may be used as promising xylanase producing candidates for various industrial purposes using agricultural based waste residues.

Inhibition of Biofilm Formation in Some Pathogenic Gram Negative Bacteria by Anti-quorum Sensing Compounds

The present study included collecting of 125 clinical bacterial isolates from different sources such as pus, sputum, nasal polyps, urine and blood. The collected bacterial isolates were preliminary identified by biochemical tests as 44 Pseudomonas spp., 35Klebsiella spp., 18E. coli, 17 Acinetobacter spp., 8 Proteus spp. and 3Enterobacter spp., The test for biofilm formation in these isolates was carried out by using three different methodsthat finally resulted in 27 positive biofilm forming isolates. Production of quorum sensing signal molecules (acyl homoserine lactone) was detected in 20 isolatesusing gas chromatography mass spectrum (GC/MS); These isolates were 3 Pseudomonas spp., 6 Klebsiella spp., 8 E. coli and 3 Enterobacter spp.,The anti-biofilm activity of some plant extracts was carried out using tube method. It showed that Syzygiumaromaticum was the most effective one and inhibited biofilm formation in all isolates followed by Allium sativum.Syzygiumaromaticum extract also inhibited quorum sensing production in the selected 20 bacterial isolates. From the above results,Syzygiumaromaticumextract was recommended to be used as an active antibacterial agent against multidrug resistant bacteria due to its ability to inhibit biofilm formation and quorum sensing signal production.Finally, the most potent bacterial isolates were genetically identified by 16S rRNA gene sequencing.

Potential of Bacterial Isolates from a Stream in Manaus-Amazon to Bioremediate Chromium-Contaminated Environments

Igarapé do Quarenta (IgQ), a stream located in the Manaus-AM, BR, has directly experienced the impacts of urban expansion over the last five decades, which contributed for its contamination. As an affluent of Rio Negro, IgQ also affects the water quality of this important river that bathes Manaus. However, the stress caused by the prolonged exposition to chemical agents may have selected microorganisms that exhibit great bioremediation potential. In the present study, bacteria isolated from four distinct sites of the IgQ were identified, and their potential to degrade hexavalent chromium (Cr(VI)) was investigated using the s-diphenylcarbazide method. Among the investigated isolates, 14 exhibited resistance against Cr(VI) at a concentration of 300 mg/L and eight isolates reduced over 50% (53.5–97.4%) chromium ratios after 72 h of incubation. Those isolates were identified by gene sequencing and classified in 10 genera (Acidovorax sp., Acinetobacter sp., Alicycliphilus sp., Bacillus sp., Comamonas sp., Enterobacter sp., Micrococcus sp., Proteus sp., Serratia sp., and Vagococcus sp.). Under control conditions, the isolate of Vagococcus sp. genus, in only 24 h of incubation, reduced 96.8% of the rate of Cr(VI) added to the culture medium at the concentration of 10 mg/L. Obtained results indicate that the Vagococcus sp. exhibits a great potential to be used in the bioremediation of areas contaminated with chromium. The mechanisms of action of microorganisms should be investigated for more specific applications in the decontamination of effluents and direct use of its by-products to bioremediate polluted environments.

Identification of Gene Encoding Organophosphorus Hydrolase (OPH) Enzyme in Potent Organophosphates-degrading Bacterial Isolates

Identification of Gene Encoding Organophosphorus Hydrolase (OPH) Enzyme in Potent Organophosphates-degrading Bacterial Isolates

Bioplastic reservoir of diverse bacterial communities revealed along altitude gradient of Pangi-Chamba trans-Himalayan region.

Himalaya hosts a unique environment for microbial ecology. The present study aimed to explore the bioplastic producing bacterial communities along altitude gradient of Pangi-Chamba trans-Himalayan region. A total of 411 bacteria were isolated and 70 characterized at the molecular level for potential polyhydroxyalkanoates (PHA) producers. The most abundant phylum for PHA synthesis was Proteobacteria (73%), followed by Actinobacteria (11%), Firmicutes (10%) and Bacteroidetes (6%). However, at the genus level, Pseudomonas and Janthinobacterium were dominantly reported. Also, the ability to synthesize PHA was reported for the first time for few genera such as Collimonas, Pseudarthrobacter and Paenarthrobacter. Phylogenetic analysis of partial 16S rDNA and phaC genes revealed conservation in phaC and possibility of horizontal gene transfer among distant taxa. Furthermore, GC-MS also confirmed the ability of potential bacterial isolates to synthesize PHA. In fact, we found that PHA-positive bacteria are dominant in the high altitude of Himalaya, suggesting the vital role of PHA in bacterial adaptation and survival. Together, these findings had revealed the rich bacterial diversity and genetic machinery for PHA synthesis which does have potential for further utilization in the commercial applications.

Biosorption of multi-heavy metals by coral associated phosphate solubilising bacteria Cronobacter muytjensii KSCAS2

This paper examines the potential detoxification efficiency of heavy metals by phosphate solubilising bacteria (PSB) that were isolated from coral, sea grass and mangrove environment. Initially, four potential bacterial isolates were selected based on their phosphate solubilisation index from 42 strains and were used for the metal tolerance test. Among the four isolates, KSCAS2 exhibited maximum tolerance to heavy metals and the phenotype indicated the production of extra polymeric substances. In a multi-heavy metal experimental setup at two concentrations (100 and 200 mg L−l), it has been demonstrated that the bacteria have extracellularly sequestered metal ions in amorphous deposits and this has been confirmed by scanning electron microscopy. In experiments with a 100 mg L−1 initial metal concentration, the percentages of metal removal by bacteria were 55.23% of Cd, 72.45% of Cr, 76.51% of Cu and 61.51% of Zn, respectively. In subsequent experiments, when the metal concentration was increased up to 200 mg L-l, the metal removal capacity decreased as follows: 44.62%, 63.1%, 67% and 52.80% for Cd, Cr, Cu and Zn, respectively. In addition, the biosorption of heavy metals was confirmed by the Fourier transform infrared Spectroscopy (FT-IR) and scanning electron microscopy (SEM) analysis. The heavy metal concentrations in a broth culture were analysed by inductively coupled plasma-optical emission spectroscopy (ICP-OES). The study suggests that PSB Cronobacter muytjensii KSCAS2 can efficiently remove the heavy metals and these bacteria could be used for the metal removal from the agricultural soils.

Biological control of watermelon seedling blight caused by Acidovorax citrulli using antagonistic bacteria from the genera Curtobacterium, Microbacterium and Pseudomonas

The biological control of the watermelon seedling blight and fruit blotch disease was investigated by screening the potential use of antagonistic bacteria. Between May and August 2012, totally 322 putative antagonistic bacteria were isolated from symptomless melon and watermelon plants grown in Adana, Hatay, and Osmaniye provinces of the Eastern Mediterranean Region of Turkey. In vitro dual culture tests showed that 54 out of 322 strains inhibited the Acidovorax citrulli (Ac) growth with an appearance of clear zones between 2.3 and 27.0 mm in diameter. However, the remaining 268 strains did not exhibit any antagonistic activity against Ac. Seed treatments with fourteen individual antagonistic bacteria resulted in a significant reduction in disease incidence (DI) and severity (DS) ranging between 14.06–79.47% and between 4.57–41.49%, respectively. The bacteria Pseudomonas oryzihabitans (Antg-12), Microbacterium oxydans (Antg-57), Curtobacterium flaccumfaciens (Antg-198), and Pseudomonas fluorescens (Antg-273) were the most potent antagonistic bacterial isolates which reduced DI and DS as compared to the untreated control. This study suggested the potential of bacterial antagonists Curtobacterium flaccumfaciens, Microbacterium oxydans, Pseudomonas oryzihabitans, and Pseudomonas fluorescens for the biocontrol of Ac-induced bacterial fruit blotch (BFB).