Journal of Environmental Biology
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Browsing Journal of Environmental Biology by Subject "16S rDNA"
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Item Characterization and optimization of bacterial cellulose produced by Acetobacter spp.(Triveni Enterprises, 2020-03) Anusuya, R.S.; Anandham, R.; Kumutha, K.; Gayathry, G.; Vellaisamy, M.; Uthandi, S.im: The study aimed to search for a potential bacterial strain capable of producing maximal bacterial cellulose under optimized conditions for future scale up.Methodology: Eight cellulose producing bacterial strains were isolated from sugarcane juice using Hestrin and Schramm (HS) medium. These isolates were identified through 16S rDNA based on molecular phylogenetic approach and the cellulose mat was analyzed for their physico-chemical properties. Morphological, chemical and physical properties of cellulose mat was studied by Scanning Electron Microscopy, Fourier Transform Infrared Spectroscopy spectrum, High Performance Liquid Chromotograpy and Differential Scanning Calorimetry. Optimal nutrient composition for maximum cellulose production by the isolate was carried out by response surface methodology.Results: 16S rDNA sequence analysis revealed that the isolates belonged to Acetobacter senegalensis, Acetobacter thailandicus, Acetobacter lambici, Acetobacter lovaniensis and Acinetobacter baumannii. Among them, A. senegalensis MA1 produced the maximum cellulose mat of dry weight 3.6 g per 500 ml of HS medium after 2 weeks of incubation. The morphology of bacterial cellulose produced by A. senegalensis MA1 had a pellicle shaped distinguished network structure and the rod shaped bacterium was attached to the bottom of cellulose mat. HPLC analysis revealed that the peaks obtained from bacterial cellulose were almost similar to carboxymethyl cellulose (CMC) peak. In cellulose mat, the weight of carbon, oxygen were 60.13 and 25.12, respectively. Analysis of differential scanning calorimetry showed endothermal peak at 139.8°C., indicating the melting point of bacterial cellulose mat. Through response surface methodology analysis, 5 g of glycerol and 1.2 g of yeast extract per 100 ml medium was optimized to get maximum cellulose production (2.04 g) from A. senegalensis MA1. Interpretation: Optimized condition for maximum bacterial cellulose production may be applied at industrial scale for commercial utilizationItem Characterization of cultural beneficial bacterial diversity for plant growth promoting attributes associated with rice rhizosphere(Triveni Enterprises, 2019-11) Sharma, L.; Shukla, S.K.; Jaiswal, V.P.; Sharma, K.K.Aim: The study was undertaken to isolate, characterize and molecularly identify plant growth promoting rhizobacteria (PGPR) associated with rice rhizosphere occurring in Gangetic plains of the country. Methodology: One hundred forty three plant growth promoting rhizobacteria were isolated on various culture media and characterized culturally and morphologically through Scanning Electron Microscope. These rhizobacterial isolates were further screened for plant growth promoting activities like HCN production, siderophore production and phosphate solubilisation. The 16S rDNA sequencing was done to decipher phylogenetic relationship among 19 selected PGPRs. Besides, these were also tested for anti-oxidative enzyme production to mitigate deleterious effects of various stresses on plant growth and metabolism. Results: Nineteen potential plant growth promoting rhizobacteria were characterized for plant growth promoting attributes and were indentified at molecular level. Rice is well colonized by bacteria mainly Bacillus spp., Pseudomonas spp., Burkholderia sp., and Acinetobactor spp., Rice seeds treated with microbial consortium of MAU 143 + MRT 84 recorded in increased antioxidant production–SOD activity (0.02 U mg−1 f.w.t.), POX activity (0.16 U mg−1 f.w.t.), POP activity (0.06 U mg−1 f.w.t.) and TPC assay (1.17 µg gallic acid mg-1 extract) which might have stimulated the growth of radical (2.2 cm) and plumule (1.6 cm) over control. These three PGPRs viz., MAU 143, MRT 84 and MRT 92 strain showed great potential to improve antioxidant and total polyphenol production and seed vigour of rice seedlings. The identified rhizobacterial strains may be used for plant growth promotion and improvement in nutrients mobilization and oxidative stresses in rice production. Interpretation: The study suggested that plant growth promoting rhizobacteria isolated from rice rhizosphere have greater potential to improve soil nutrients status while provide resistance against infection of pathogenic microbes due to production of anti-oxidative enzymes and phenolic compounds in rice seedlings.Item Characterization of Xanthomonas campestris pv. viticola causing bacterial leaf spot of grapes in Maharashtra, India(Triveni Enterprises, 2019-11) Kamble, A.K.; Sawant, S.D.; Sawant, I.S.; Ghule, S.B.; Patil, A.C.; Saha, S.Aim: The aim of the present study was to isolate, characterize and identify pathogenic bacteria from bacterial leaf spot infected grape vineyards of Maharashtra. Methodology: Collected diseased samples were subjected to isolation. All isolates were further subjected to different morphological and biochemical characterization. These isolates were also used to standardize inoculation methods to study host range and test pathogenicity to confirm infectivity. Genomic DNA was isolated from bacteria for phylogeneitc analysis using 16 rDNA. Results: The disease is characterized by water soaked, angular leaf spot which later turns to irregular, dark brown to black necrotic region on the leaf surface. Microbial studies confirmed that it is a Gram negative, rod shaped bacterium with white, mucoid, glistening and convex circular colonies on artificial medium. Pathogenicity test was performed to confirm virulence. Phylogenetic analysis of 16S rDNA gene exhibited more than 99% similarity with other Xanthomonas campestris pv. viticola. The bacterium was found resistant to vancomycin, peniciliin and oxacillin antibiotics. The bacterium is also capable of infecting Mangifera indica and Citrus limon along with eight weed species.Item Studies on the distribution of bacterial isolates in rare earth environment.(2012-01) Selvam, A; Emmanuel, E S Challaraj; Anandkumar, B; Maruthamuthu, S; Palaniswamy, NRare earth soil is precious, but very common across Arabian coast especially in Chavara, (Quilon district, Kerala) south west coast of India. They are widely distributed but usually occur in small amounts and enhance the soil properties. In the present study, 18 different bacterial isolates were identified from three different samples such as soil and biofilm formed on metal surfaces from the rare earth environment of Chavara using 16S rDNA gene sequencing. The accumulation of rare earth elements (REE) by microbes was studied using FT-IR analysis. In the FTIR spectrum of the test system, a peak at 1548 and 1449 cm-1 indicates the presence of aromatic nuclei (carboxylic acid), while C=C stretch for C-O-C group was noticed at 1237 cm-1. Thus significant variations in the peak position confirm the presence of carboxyl group and thus it was confirmed that rare earth elements induce the bacteria to produce carboxylic acid and thereby accumulate rare earth elements.