scholarly journals Screening of Silver-Tolerant Bacteria from a Major Philippine Landfill as Potential Bioremediation Agents

2018 ◽  
Vol 25 (3) ◽  
pp. 469-485 ◽  
Author(s):  
Joan S. Adriano ◽  
Glenn G. Oyong ◽  
Esperanza C. Cabrera ◽  
Jose Isagani B. Janairo

Abstract The field of microbial biotechnology has revolutionized the utilization of microorganisms to overcome the problems of environmental pollutions. The present study aimed to identify silver-tolerant isolates and screen their ability to synthesize silver nanoparticles for possible use as bioremediation agents. Seventeen bacterial isolates from soil collected from the Smokey Mountain landfill in Manila, Philippines, were found to tolerate 0.01 M AgNO3 in the culture medium. Molecular and phylogenetic analyses using the 16S rRNA gene sequence identified the isolates as Bacillus cereus, Bacillus subtilis, Bacillus flexus, Bacillus thuringiensis, Alcaligenes faecalis, Achromobacter sp. and Ochrobactrum sp. The formation of silver nanoparticles was evident in the change in color of the reaction mixtures, and was detected through UV-VIS spectroscopy with absorbance peaks at 250-300 nm and 400-450 nm. Scanning electron microscopy revealed the aggregation of diverse shapes of silver nanoparticles with sizes ranging from 70 to 200 nm. The best silver nanoparticle-synthesizing isolates were Alcaligenes faecalis and Bacillus cereus. The results denote the promising microbial technology application of the 17 silver-tolerant isolates in combating the adverse effects of metals and other pollutants in the environment.

Pathogens ◽  
2020 ◽  
Vol 9 (3) ◽  
pp. 160 ◽  
Author(s):  
Temoor Ahmed ◽  
Muhammad Shahid ◽  
Muhammad Noman ◽  
Muhammad Bilal Khan Niazi ◽  
Faisal Mahmood ◽  
...  

Amongst serious biotic factors deteriorating crop yield, the most destructive pathogen of rice is Xanthomonas oryzae pv. oryzae (Xoo), which causes bacterial leaf blight (BLB) disease. This study involved targeted use of biogenic silver nanoparticles (AgNPs) to control BLB in order to cope with the disadvantages of chemical disease control. AgNPs were biologically synthesized from natively isolated Bacillus cereus strain SZT1, which was identified through 16S rRNA gene sequence analysis. Synthesis of AgNPs in bacterial culture supernatant was confirmed through UV-VIS spectroscopy. Fourier transform infrared spectroscopy (FTIR) confirmed that the existence of AgNPs was stabilized with proteins and alcoholic groups. X-ray diffraction (XRD) data revealed the crystalline nature and imaging with scanning electron microscopy (SEM) and transmission electron microscopy (TEM), showing the spherical shape of AgNPs with particle sizes ranging from 18 to 39 nm. The silver presence in AgNPs was further confirmed by energy dispersive spectra. Biogenic AgNPs showed substantial antibacterial activity (24.21 ± 1.01 mm) for Xoo. In a pot experiment, AgNPs were found to be effective weapons for BLB by significantly increasing the plant biomass with a decreased cellular concentration of reactive oxygen species and increased concentration of antioxidant enzyme activity.


2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Pankaj Kumar ◽  
Vikas Pahal ◽  
Arti Gupta ◽  
Ruchi Vadhan ◽  
Harish Chandra ◽  
...  

AbstractThe effect of Plant Growth Promoting Rhizobacteria (Bacillus sp.) and silver nanoparticles on Zea mays was evaluated. The silver nanoparticles were synthesized from Tagetes erecta (Marigold) leaf and flower extracts, whereas PGPR isolated from spinach rhizosphere. The silver nanoparticles (AgNPs) were purified using ultra centrifugation and were characterized using UV–Vis spectroscopy at gradient wavelength and also by High Resolution Transmission Electron microscopy (HRTEM). The average particles size of AgNPs was recorded approximately 60 nm. Almost all potential isolates were able to produce Indole Acetic Acid (IAA), ammonia and Hydrogen cyanide (HCN), solubilized tricalcium phosphate and inhibited the growth of Macrophomina phaseolina in vitro but the isolate LPR2 was found the best among all. On the basis of 16S rRNA gene sequence, the isolate LPR2 was characterized as Bacillus cereus LPR2. The maize seeds bacterized with LPR2 and AgNPs individually showed a significant increase in germination (87.5%) followed by LPR2 + AgNPs (75%). But the maximum growth of root and shoot of maize plant was observed in seeds coated with LPR2 followed by AgNPs and a combination of both. Bacillus cereus LPR2 and silver nanoparticles enhanced the plant growth and LPR2 strongly inhibited the growth of deleterious fungal pathogen. Therefore, LPR2 and AgNPs could be utilized as bioinoculant and growth stimulator, respectively for maize.


2004 ◽  
Vol 54 (1) ◽  
pp. 175-181 ◽  
Author(s):  
Costantino Vetriani ◽  
Mark D. Speck ◽  
Susan V. Ellor ◽  
Richard A. Lutz ◽  
Valentin Starovoytov

A thermophilic, anaerobic, chemolithoautotrophic bacterium was isolated from the walls of an active deep-sea hydrothermal vent chimney on the East Pacific Rise at 9° 50′ N. Cells of the organism were Gram-negative, motile rods that were about 1·0 μm in length and 0·6 μm in width. Growth occurred between 60 and 80 °C (optimum at 75 °C), 0·5 and 4·5 % (w/v) NaCl (optimum at 2 %) and pH 5 and 7 (optimum at 5·5). Generation time under optimal conditions was 1·57 h. Growth occurred under chemolithoautotrophic conditions in the presence of H2 and CO2, with nitrate or sulfur as the electron acceptor and with concomitant formation of ammonium or hydrogen sulfide, respectively. Thiosulfate, sulfite and oxygen were not used as electron acceptors. Acetate, formate, lactate and yeast extract inhibited growth. No chemoorganoheterotrophic growth was observed on peptone, tryptone or Casamino acids. The genomic DNA G+C content was 54·6 mol%. Phylogenetic analyses of the 16S rRNA gene sequence indicated that the organism was a member of the domain Bacteria and formed a deep branch within the phylum Aquificae, with Thermovibrio ruber as its closest relative (94·4 % sequence similarity). On the basis of phylogenetic, physiological and genetic considerations, it is proposed that the organism represents a novel species within the newly described genus Thermovibrio. The type strain is Thermovibrio ammonificans HB-1T (=DSM 15698T=JCM 12110T).


2006 ◽  
Vol 188 (9) ◽  
pp. 3345-3356 ◽  
Author(s):  
Craig Everroad ◽  
Christophe Six ◽  
Frédéric Partensky ◽  
Jean-Claude Thomas ◽  
Julia Holtzendorff ◽  
...  

ABSTRACT Chromatic adaptation (CA) in cyanobacteria has provided a model system for the study of the environmental control of photophysiology for several decades. All forms of CA that have been examined so far (types II and III) involve changes in the relative contents of phycoerythrin (PE) and/or phycocyanin when cells are shifted from red to green light and vice versa. However, the chromophore compositions of these polypeptides are not altered. Some marine Synechococcus species strains, which possess two PE forms (PEI and PEII), carry out another type of CA (type IV), occurring during shifts from blue to green or white light. Two chromatically adapting strains of marine Synechococcus recently isolated from the Gulf of Mexico were utilized to elucidate the mechanism of type IV CA. During this process, no change in the relative contents of PEI and PEII was observed. Instead, the ratio of the two chromophores bound to PEII, phycourobilin and phycoerythrobilin, is high under blue light and low under white light. Mass spectroscopy analyses of isolated PEII α- and β-subunits show that there is a single PEII protein type under all light climates. The CA process seems to specifically affect the chromophorylation of the PEII (and possibly PEI) α chain. We propose a likely process for type IV CA, which involves the enzymatic activity of one or several phycobilin lyases and/or lyase-isomerases differentially controlled by the ambient light quality. Phylogenetic analyses based on the 16S rRNA gene confirm that type IV CA is not limited to a single clade of marine Synechococcus.


2006 ◽  
Vol 56 (6) ◽  
pp. 1305-1310 ◽  
Author(s):  
Jan Hendrik Wübbeler ◽  
Tina Lütke-Eversloh ◽  
Stefanie Van Trappen ◽  
Peter Vandamme ◽  
Alexander Steinbüchel

In this study, a novel betaproteobacterium, strain DPN7T, was isolated under mesophilic conditions from compost because of its capacity to utilize the organic disulfide 3,3′-dithiodipropionic acid. Analysis of the 16S rRNA gene sequence of strain DPN7T revealed 98.5 % similarity to that of Tetrathiobacter kashmirensis LMG 22695T. Values for sequence similarity to members of the genera Alcaligenes, Castellaniella and Taylorella, the nearest neighbours of the genus Tetrathiobacter, were about 95 % or less. The DNA G+C content of strain DPN7T was 55.1 mol%. The level of DNA–DNA hybridization between strain DPN7T and T. kashmirensis LMG 22695T was 41 %, whereas it was much lower between strain DPN7T and Alcaligenes faecalis LMG 1229T (7 %) or Castellaniella defragrans LMG 18538T (5 %). This genotypic divergence was supported by differences in biochemical and chemotaxonomic characteristics. For this reason, and because of the differences in the protein and fatty acid profiles, strain DPN7T should be classified within a novel species of Tetrathiobacter, for which the name Tetrathiobacter mimigardefordensis sp. nov. is proposed. The type strain is strain DPN7T (=DSM 17166T=LMG 22922T).


Phytotaxa ◽  
2020 ◽  
Vol 442 (2) ◽  
pp. 61-79 ◽  
Author(s):  
DENIS DAVYDOV ◽  
SERGEI SHALYGIN ◽  
ANNA VILNET

A cyanobacterial strain isolated from the Svalbard archipelago was studied using morphological, ecological, and molecular approaches. The morphology of natural populations fit well the description of the Leptolyngbya s.l. however, in culture, they formed specific nodules that prevented affiliation to this genus. Further phylogenetic analyses including the 16S rRNA gene and 16S-23S ITS region revealed that the strain corresponds to the genus Nodosilinea. Based on this total evidence approach, we provide here a description of the new taxon Nodosilinea svalbardensis sp. nov.


2007 ◽  
Vol 57 (5) ◽  
pp. 959-963 ◽  
Author(s):  
Jaewoo Yoon ◽  
Mina Yasumoto-Hirose ◽  
Atsuko Katsuta ◽  
Hiroshi Sekiguchi ◽  
Satoru Matsuda ◽  
...  

An obligately aerobic, Gram-negative, non-spore-forming, non-motile, spherical bacterium, designated strain 04OKA010-24T, was isolated from seawater surrounding the hard coral Galaxea fascicularis L., collected at Majanohama, Akajima, Japan, and was subjected to a polyphasic taxonomic study. Phylogenetic analyses based on the 16S rRNA gene sequence indicated that the new strain represented a member of the phylum ‘Verrucomicrobia’ and shared 84–95 % sequence similarity with cultivated strains of ‘Verrucomicrobia’ subdivision 4. Amino acid analysis of the cell-wall hydrolysate indicated the absence of muramic acid and diaminopimelic acid, which suggested that the strain did not contain peptidoglycan in the cell wall. The G+C content of the DNA was 53.9 mol%. MK-7 was the major menaquinone and C14 : 0, C18 : 1 ω9c and C18 : 0 were the major fatty acids. On the basis of these data, it was concluded that strain 04OKA010-24T represents a novel species in a new genus in subdivision 4 of the phylum ‘Verrucomicrobia’, for which the name Coraliomargarita akajimensis gen. nov., sp. nov. is proposed. The type strain of Coraliomargarita akajimensis is 04OKA010-24T (=MBIC06463T=IAM 15411T=KCTC 12865T).


2006 ◽  
Vol 56 (12) ◽  
pp. 2831-2836 ◽  
Author(s):  
Marie Bank Nielsen ◽  
Kasper Urup Kjeldsen ◽  
Kjeld Ingvorsen

A novel alkalitolerant, anaerobic bacterium, designated strain sk.kt5T, was isolated from a metal coupon retrieved from a corrosion-monitoring reactor of a Danish district heating plant (Skanderborg, Jutland). The cells of strain sk.kt5T were motile, rod-shaped (0.4–0.6×2.5–9.6 μm), stained Gram-positive and formed endospores. Strain sk.kt5T grew at pH 7.6–10.5 (with optimum growth at pH 8.0–9.5), at temperatures in the range 23–44 °C (with optimum growth at 35–37 °C), at NaCl concentrations in the range 0–5 % (w/v) (with optimum growth at 0–0.5 %) and required yeast extract for growth. Only a limited number of substrates were utilized as electron donors, including betaine, formate, lactate, methanol, choline and pyruvate. Elemental sulfur, sulfite, thiosulfate, nitrate and nitrite, but not sulfate or Fe(III) citrate, were used as electron acceptors. The G+C content of the DNA was 41.6 mol%. Phylogenetic analyses of the sequence data for the dsrAB genes [encoding the major subunits of dissimilatory (bi)sulfite reductase] and the 16S rRNA gene placed strain sk.kt5T within a novel lineage in the class Clostridia of the phylum Firmicutes. Taken together, the physiological and genotypic data suggest that strain sk.kt5T represents a novel species within a novel genus, for which the name Desulfitibacter alkalitolerans gen. nov., sp. nov. is proposed. The type strain of Desulfitibacter alkalitolerans is sk.kt5T (=JCM 12761T=DSM 16504T).


2010 ◽  
Vol 60 (11) ◽  
pp. 2629-2633 ◽  
Author(s):  
Tomohiko Tamura ◽  
Yuumi Ishida ◽  
Misa Otoguro ◽  
Ken-ichiro Suzuki

Three short spore chain-forming actinomycete strains were isolated from soil samples collected from subtropical islands in Japan. The cell-wall peptidoglycan of these strains contained meso-diaminopimelic acid (meso-A2pm), glutamic acid and alanine. The major isoprenoid quinone was MK-9(H4), iso-C16 : 0 and 2-OH iso-C16 : 0 were the major cellular fatty acids and phosphatidylethanolamine was a component of the polar lipids. The G+C content of the genomic DNA was 67–69 mol%. Phylogenetic analyses based on the 16S rRNA gene sequences showed that the novel strains consistently formed a monophyletic cluster with Amycolatopsis taiwanensis. On the basis this polyphasic taxonomical study, it is proposed that the two new isolates represent two novel species: Amycolatopsis helveola (type strain TT00-43T=NBRC 103394T=KCTC 19329T) and Amycolatopsis pigmentata (type strain TT99-32T=NBRC 103392T=KCTC 19330T).


2007 ◽  
Vol 57 (5) ◽  
pp. 1035-1040 ◽  
Author(s):  
André Antunes ◽  
Luis França ◽  
Fred A. Rainey ◽  
Robert Huber ◽  
M. Fernanda Nobre ◽  
...  

Two moderately halophilic Gram-negative bacteria were isolated from a sample taken from the brine–seawater interface of the Shaban Deep in the Red Sea. Phylogenetic analysis of the 16S rRNA gene sequence showed that these organisms represent a novel species of the genus Marinobacter. Cells of the new isolates formed non-pigmented colonies and were motile by means of a single polar flagellum. Strains SD-14BT and SD-14C grew optimally at 35–37 °C, in 5 % NaCl and at pH 7.5–8.0. The organisms were aerobic, but reduced nitrate to nitrogen under anaerobic conditions. Acid was produced from only a few carbohydrates. Ubiquinone 9 was the major respiratory quinone. The major fatty acids of strains SD-14BT and SD-14C were C16 : 0, C18 : 1 ω9c, summed feature 3 (C16 : 1 ω6c/C16 : 1 ω7c) and C12 : 0 3-OH. The DNA G+C contents were 55.9 and 55.7 mol%, respectively. On the basis of the phylogenetic analyses and physiological and biochemical characteristics, it is proposed that strains SD-14BT and SD-14C represent a novel species of the genus Marinobacter, with the name Marinobacter salsuginis sp. nov. The type strain is strain SD-14BT (=DSM 18347T=LMG 23697T).


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