ABSTRACT
Pseudomonas aeruginosa causes life-threatening diseases and is resistant to almost all conventional antibiotics. The quorum sensing (QS) system of P. aeruginosa contributes to many pathogenic factors some of which are pigment production, motility, and biofilm. The disruption of quorum sensing system may be an impactful strategy to deal with infections. The present study investigates the anti-quorum sensing property of a bioactive molecule extracted from marine epibiotic bacteria present on the surface of seaweeds. Among all the isolates tested against monitor strain Chromobacterium violaceum (MTCC 2656), the one with the highest activity was identified as Bacillus zhangzhouensis SK4. The culture supernatant was extracted with chloroform which was then partially purified by TLC and column chromatography. The probable anti-QS compound was identified as 1,2-benzenedicarboxylic acid, bis (2-methylpropyl ester) by GC-MS and NMR analysis. The treatment of P. aeruginosa MCC 3457 with the lead compound resulted in the reduced production of pyocyanin, rhamnolipids, exopolysaccharide, biofilm, and motility. The observations of light and scanning electron microscopy also supported the biofilm inhibition. The lead compound showed synergism with the meropenem antibiotic and significantly reduced MIC. The molecular docking and pharmacokinetics study predicted 1, 2-benzenedicarboxylic acid, bis (2-methylpropyl ester), a phthalate derivative as a good drug candidate. The molecular dynamics study was also performed to check the stability of the lead compound and LasR complex. Further, lead compounds did not exhibit any cytotoxicity when tested on human embryonic kidney cells. As per our knowledge, this is the first report on the anti-QS activity of B. zhangzhouensis SK4, indicating that epibiotic bacteria can be a possible source of novel compounds to deal with the multidrug resistance phenomenon.
Subject(s)
Anti-Bacterial Agents , Bacillus , Biofilms , Molecular Docking Simulation , Pseudomonas aeruginosa , Quorum Sensing , Virulence Factors , Quorum Sensing/drug effects , Pseudomonas aeruginosa/drug effects , Biofilms/drug effects , Biofilms/growth & development , Virulence Factors/metabolism , Humans , Anti-Bacterial Agents/pharmacology , Anti-Bacterial Agents/chemistry , Anti-Bacterial Agents/isolation & purification , Bacillus/drug effects , Bacillus/chemistry , Bacillus/metabolism , Chromobacterium/drug effects , Microbial Sensitivity Tests , Pyocyanine/metabolism , Bacterial Proteins/metabolism , Glycolipids/pharmacology , Glycolipids/chemistry , Polysaccharides, Bacterial/pharmacology , Polysaccharides, Bacterial/isolation & purification , Polysaccharides, Bacterial/chemistry , Polysaccharides, Bacterial/metabolismABSTRACT
Haloarchaea are found at very high concentrations in salt-conditioned environments, hence produce enzymes which are able to catalyze reactions under harsh conditions, typical of many industrial processes. In the present study, culture conditions for extracellular amylase production from Haloarchaea isolated from a solar saltern were optimized and the purified enzyme was characterized. Haloferax sp. HA10 showed maximum amylase production at 3 M NaCl, 37 °C, pH=7 and 1% starch content. Purified α-amylase was a calcium-dependent enzyme with an estimated molecular mass of about 66 kDa and many industrially useful properties. It was found to be stable in a broad range of pH (from 5 to 9) and NaCl concentrations (from 0.5 to 3.0 M), retaining 48% activity even at 4 M. The optimal temperature for Haloferax sp. HA10 amylase activity was 55 °C (99% activity), and 57% activity was retained at 80 °C, which dropped to 44% with the increase of temperature to 90 or 100 °C. It was able to sustain various surfactants and detergents. To the best of our knowledge the detergent-stable α-amylases from halophilic archaeon have not been reported yet.
ABSTRACT
In a new approach to microbial gallic acid production by Aspergillus fischeri MTCC 150, 40gL-1 oftannic acid was added in two installments during the bioconversion phase of the process (25gL-1 and 15gL-1 at 32 and 44h respectively). The optimum parameters for the bioconversion phase were found to be temperature: 35ºC, pH: slightly acidic (3.3-3.5), aeration: nil and agitation: 250 rpm. A maximum of 71.4 percent conversion was obtained after 71h fermentation with 83.3 percent product recovery. The yield was 7.35 g of gallic acid per g of biomass accumulated and the fermenter productivity was 0.56 g of gallic acid produced per liter of medium per hour.
Em uma nova abordagem para produção de ácido gálico por Aspergillus fischeri MTCC 150, adiciona-se 40 g.L-1 de ácido tânico em dois momentos da fase de bioconversão do processo (25 g.L-1 e 15 g.L-1 a 32h e 44h, respectivamente). Os parâmetros ótimos para a fase de bioconversão foram: temperatura 35ºC, pH levemente ácido (3,3 a 3,5), nenhuma aeração e agitação 250 rpm. Um máximo de 71,4 por cento de conversão foi obtido após 71h de fermentação, com 83,3 por cento de recuperação do produto. O rendimento foi 7,35g de ácido gálico por g de biomassa acumulada e a produtividade do fermentador foi 0,56g de ácido gálico por litro de meio por hora.
Subject(s)
Gallic Acid/analysis , Gallic Acid/metabolism , Biomass , Efficiency , Fermentation , Tanacetum parthenium/metabolism , Biotransformation , Methods , Reference Standards , MethodsABSTRACT
In a new approach to microbial gallic acid production by Aspergillus fischeri MTCC 150, 40gL(-1) of tannic acid was added in two installments during the bioconversion phase of the process (25gL(-1) and 15gL(-1) at 32 and 44h respectively). The optimum parameters for the bioconversion phase were found to be temperature: 35°C, pH: slightly acidic (3.3-3.5), aeration: nil and agitation: 250 rpm. A maximum of 71.4% conversion was obtained after 71h fermentation with 83.3% product recovery. The yield was 7.35 g of gallic acid per g of biomass accumulated and the fermenter productivity was 0.56 g of gallic acid produced per liter of medium per hour.
