RESUMEN
Biological synthesis of nanoparticles is cost-effective as well as safer than physical and chemical methods. This study focuses on the biological synthesis of silver nanoparticles using Glutamicibacter uratoxydans which remains still unexplored. The synthesized silver nanoparticles are encapsulated with chitosan to prepare nanobiocomposite. Actinobacteria were isolated from mesophilic soil and screened for heavy metal resistance. The potent heavy metal resistant isolate was identified by 16SrRNA sequencing and used for the biological synthesis of silver particles. The characterization of chitosan- silver nano-bio composite was carried out by UV-Vis spectroscopy, FTIR spectroscopy, and XRD. Morphology was analyzed by scanning electron microscopy. The particle size and stability were studied using Dynamic light scattering and Zeta potential analysis. The nano-bio composite was tested for lead removal efficiency and antibiofilm activity. The potent isolate was identified as Glutamicibacter uratoxydans and it was named as Glutamicibacter uratoxydans VRAK 24. The UV spectra showed maximum absorbance at 410 nm. The FTIR spectra and XRD confirmed chitosan encapsulation with silver nanoparticle. The size of nanobiocomposite was found to be 0.376. The stability of nanobiocomposite recorded a zeta potential value of -5.37 mV. The lead removal efficiency was found to be 87.69 %. In addition, the nanobiocomposite exhibited highest anti-biofilm activity against S.aureus when compared to E.coli. The research findings, concluded that the synthesized nanobiocomposite showed better anti-biofilm activity. Also, nanobiocomposite was found to be a good adsorbent for the removal of heavy metal lead.
Asunto(s)
Quitosano , Nanopartículas del Metal , Plata/farmacología , Plata/química , Antibacterianos/química , Nanopartículas del Metal/química , Quitosano/farmacología , Quitosano/química , Espectroscopía Infrarroja por Transformada de Fourier , Biopelículas , Pruebas de Sensibilidad MicrobianaRESUMEN
AIM: Simultaneous management of FOL and RKN causing wilt complex in tomato by chaetoglobosin-producing Chaetomium globosum. METHODS AND RESULTS: Random survey was carried out to isolate Fusarium and Chaetomium. Twelve Fusarium isolates were characterized, and FOL4 (virulent) was molecularly identified. Wilt complex by FOL, RKN was assessed individually and in combination under greenhouse. RKN (1000 juveniles ml-1) inoculation followed by FOL4 (5 × 105 spores ml-1) accounted for 90% incidence. The chaetoglobosin-producing Chaetomium was isolated, characterized morphologically and molecularly. Among 55 isolates, nine showed >50% inhibition against FOL, and crude culture filtrate showed a significant reduction in RKN egg hatching (15.66%) and juvenile mortality (100%). Chaetomium Cg 40 was confirmed as C. globosum using SCAR marker (OK032373). Among 40 volatile compounds, hexadecanoic acid and 1,2-epoxy-5,9-cyclododecadiene exhibited antifungal and nematicidal properties in GC-MS. High-performance liquid chromatography revealed chaetoglobosin A (0.767 µg µl-1), and the presence of bioactive molecules chaetoglobosin (528.25 m/z), chaetomin (710 m/z), chaetocin (692.8 m/z), chaetoviridin (432.85 m/z), and chaetomugilin (390 m/z) was confirmed by LC/MS/MS. Cg 40 and Cg 6 were able to synthesize the pks1a, b gene responsible for chaetoglobosin, sporulation, and melanin biosynthesis was confirmed by PCR. The application of an aqueous formulation as seed treatment, seedling dip, and soil drenching (application) recorded lowest wilt incidence (11.11%) and gall index (1) with the maximum growth parameter (plant height 51.9 cm), fruit yield (287.5 g), and lycopene content (11.46 mg/100 g). CONCLUSIONS: Cg 40 and Cg 6, containing polyketides, secondary metabolites, antibiotics, chaetoglobosin, and plant growth-promoting ability, showed antifungal and nematicidal properties against the FOL-RKN wilt complex in tomato in vitro and pot culture experiments.
Asunto(s)
Chaetomium , Fusarium , Solanum lycopersicum , Tylenchoidea , Animales , Chaetomium/genética , Fusarium/genética , Antifúngicos/farmacología , Espectrometría de Masas en Tándem , Antinematodos/metabolismoRESUMEN
Accumulation of plastic waste has become an environmental threat and a global problem. In this research, polyethylene degrading ligninolytic bacteria were isolated from plastic waste polluted soil. Two bacterial isolates, namely PE2 and PE3 have been obtained from the soil samples. Polyethylene degrading ability of the isolates has been assessed individually in a synthetic media containing polyethylene as a carbon source. The results indicated that maximum weight reduction of polyethylene (6.68%) was found in PE3 inoculated media after thirty days of incubation. Fourier Transform Infrared Spectroscopic results showed the appearance of carbonyl peaks. 16S rRNA gene sequencing studies revealed that the potential isolate PE3 belongs to the genus Bacillus and it was named Bacillus sp. strain PE3. From the scanning electron microscopic results, it is inferred that Bacillus sp. strain PE3 could colonize on the polyethylene surface and form a biofilm. Besides, the viable Bacillus sp. strain PE3 on polyethylene surface was confirmed by fluorescence microscopic analysis. Alkanes and fatty acids were identified in the degraded products by gas chromatography-mass spectrometer analysis. From the results of native polyacrylamide gel electrophoresis, the activities of laccase and lignin peroxidase were noticed. Furthermore, extracellular production of biosurfactant has been observed in the Bacillus sp. strain PE3 inoculated mineral salt media and synthetic media with glucose and polyethylene as the carbon source respectively. The characterization studies of crude biosurfactant have confirmed that lipopeptide nature biosurfactant. The present study demonstrates that the ligninolytic enzymes laccase, lignin peroxidase, and lipopeptide type biosurfactant are produced by Bacillus sp. strain PE3 in the media with polyethylene as a carbon source.