scholarly journals Biosurfactant production by Pseudomonas aeruginosa isolated from aquaculture farm soil and its optimisation

2018 ◽  
Vol 65 (4) ◽  
Author(s):  
Ranjit kumar Nadella ◽  
Murugadas Vaiyapuri ◽  
Ahamed Basha kusunur ◽  
Toms Cheriath Joseph ◽  
Lalitha Kuttanappilly Velayudhan ◽  
...  

In the present study, aquaculture farm soil was screened for the biosurfactant producing bacteria. Total of 43 distinct morphological colonies were isolated from the farm soil and their biosurfactant production was evaluated by employing different screening methods. Fourteen biosurfactant producing bacterial isolates were selected based on the formation of dark blue halos on CTAB agar, emulsification index, oil spreading assay and BATH assay. Based on the results, bacterial isolate (BHA 9) showed highest production of biosurfactant and selected for further studies. Biochemical characterisation revealed that the bacterial isolate responsible for biosurfactant production is Gram negative, slender long rod shape bacteria and oxidase and catalase positive. Molecular characterisation of 16S r-DNArevealed that it belongs to Pseudomonas aeruginosa . Optimization studies were carried out at different temperatures (25, 30, 35 and 40 o C) using four different carbon sources (1%) i.e ., glucose, sucrose, maltose and starch and four nitrogen sources (1%) viz ., peptone, ammonium nitrate, beef extract and yeast extract at different pH (6, 7, 8, 9 and 10) and NaCl levels (0.50, 1, 1.50 and 2%). Emulsification index and the bacterial biomass (OD 600 ) were recorded at 24, 48, 72 and 96 h intervals. Optimum condition for biosurfactant production by this bacterium was achieved when glucose and yeast extract was used as carbón and nitrogen sources, respectively  maintaining a temperature of 35 o C, pH 8 and NaCl 1.5% measured in terms of emulsification index and bacterial biomass. This is the first reported study for the biosurfactant producing bacteria from aquaculture farm soil which may find its application in various fields.

2010 ◽  
Vol 2010 ◽  
pp. 1-8 ◽  
Author(s):  
Gizele Cardoso Fontes ◽  
Priscilla Filomena Fonseca Amaral ◽  
Marcio Nele ◽  
Maria Alice Zarur Coelho

In order to improve biosurfactant production byYarrowia lipolyticaIMUFRJ 50682, a factorial design was carried out. A24full factorial design was used to investigate the effects of nitrogen sources (urea, ammonium sulfate, yeast extract, and peptone) on maximum variation of surface tension (ΔST) and emulsification index (EI). The best results (67.7% of EI and 20.9 mNm−1ofΔST) were obtained in a medium composed of 10 g 1−1of ammonium sulfate and 0.5 g 1−1of yeast extract. Then, the effects of carbon sources (glycerol, hexadecane, olive oil, and glucose) were evaluated. The most favorable medium for biosurfactant production was composed of both glucose (4% w/v) and glycerol (2% w/v), which provided an EI of 81.3% and aΔST of 19.5 mN m−1. The experimental design optimization enhancedΔEI by 110.7% andΔST by 108.1% in relation to the standard process.


2021 ◽  
Vol 37 (2) ◽  
pp. 165-176
Author(s):  
W.C John ◽  
I.O Ogbonna ◽  
G.M Gberikon ◽  
C.C Iheukwumere

Biosurfactants synthesized by microorganisms are chemically diverse and have gained interest industrially due to their surface and interfacial tensions-reducing activities. In this study Bacillus species from contaminated soils were screened and characterized for biosurfactant production. The study was carried out at the Microbiology Laboratory, Federal University of Agriculture Makurdi, Nigeria. The Bacillus species were isolated from kerosene shops, palm oil shops, nearby restaurants, mechanic workshops and abattoir effluents- contaminated soil samples collected from Makurdi metropolis. The Bacillus spp. were screened for biosurfactants production potentials using various screening methods (oil spreading, beta haemolysis, drop collapse and emulsification index). Specific primers were used to amplify the srfAA (surfactin gene) gene in the Bacillus isolates and the nucleotide sequences were determined at Inqaba Biotec, South Africa. The screening results were statistically analysed using analysis of variance (ANOVA) at 95 % confidence level. Isolate RT7(4)B exhibited the ability to produce biosurfactant, as well as the highest emulsification index (E24) of 73.25 % while isolate PO7(3)C gave the highest oil displacement of 6.77 mm. The supernatant obtained from isolate RT7(4)B showed reduction in surface tension of up to 30.26 mN/m. The isolates gave positive results for biosurfactant production when subjected to drop collapse and Beta haemolytic tests. The Polymerase chain reaction (PCR) results revealed amplifications of srfAA gene from 7 isolates. Based on these findings, the isolates used in this study can be utilized for biosurfactant production, and can also be useful for bioremediation and industrial biotechnology applications. Keywords: Biosurfactants; emulsification index; Bacillus; surface tension; Drop collapse


2021 ◽  
Author(s):  
Sekar Harikrishnan ◽  
Singaram Jayalakshmi ◽  
Mohamad S. Alsalhi ◽  
Alager Kartick ◽  
Sandhanasamy Devanesan ◽  
...  

Abstract In the present work, production of biosurfactant was studied from the bacterial strains isolated from the soil samples collected from oil contaminated sites in Karaikal ONGC, Puducherry, India. Six morphologically different hydrocarbonoclastic bacterial strains (SJ1-SJ6) isolated on oil agar plates were further screened for biosurfactant production. Based on the screening methods results of 26 mm oil displacement zone, positive results of drop collapse test, 68.14% emulsification index (E24) and 79.2% of bacterial adherence percentage, the isolate SJ3 was selected as the most potent strain and it was identified as P. stutzeri using standard biochemical and 16S rRNA gene sequencing-based methods. Optimization of the P. stutzeri strain showed 36 h incubation, 150 rpm agitation, pH 7.5, 37oC, 1% salinity, 2% glucose as carbon source and 1% yeast extract as nitrogen source were the ideal conditions for growth and the biosurfactant production was found to be growth dependent. The crude biosurfactant showed broad range of antibacterial activity against the bacterial pathogens tested. The P. stutzeri isolated from oil spill site showed biosurfactant with antibacterial activities.


Author(s):  
Victor Ezebuiro ◽  
Ipeghan Jonathan Otaraku ◽  
Boma Oruwari ◽  
Gideon Chijioke Okpokwasili

Aim: This study investigated effects of nitrogen and carbon sources on the production of biosurfactant by a hydrocarbon-utilizing bacterium, Stenotrophomonas sp. Methodology: The hydrocarbon-utilizing bacterium was isolated with Bushnell Haas (BH) broth using enrichment method. Biosurfactant production was screened by evaluating the following characteristics: Emulsification index (E-24), oil spreading (displacement), tilted glass slide, haemolysis on blood agar, and lipase production. Effects of combination of nitrogen sources (yeast extract and NH4NO3, yeast extract and urea, yeast extract and asparagine, yeast extract and peptone, NaNO3 and peptone, NaNO3 and asparagine, and yeast extract and NaNO3) and carbon sources (glucose, fructose, galactose, cassava peel, soya bran, olive oil, sucrose, crude oil, diesel and glycerol) on biosurfactant production were determined with emulsion stability and surface tension as responses. The bacterium was identified based on phenotypic, microscopic, and biochemical characteristics. Results: The isolate produced colonies on BH agar containing either naphthalene or hexadecane as sole source of carbon after 48-h incubation. Screening characteristics for the production of biosurfactant by the isolate were as follows: 46% emulsification index, 3.1 cm2 oil displacement, 1.8 cm zone of clearance on tributyrin agar, γ-haemolysis, and positive tilted glass slide. The best carbon source with the highest emulsion stability (51.6%) was fructose whereas the best surface tension reduction (30.85 mN/m) was observed with olive oil as carbon sources after 7 days of incubation. For nitrogen, the combination of yeast extract and NH4NO3 gave the highest emulsion stability (60.7%) and the best surface tension reduction (39.58 mN/m). The data obtained were significant at P<0.05 and the bacterial isolate identified as Stenotrophomonas sp. Conclusion: This study has demonstrated the ability of the hydrocarbon-utilizing bacterium, Stenotrophomonas sp. to produce biosurfactant, indicated by reduction of surface tension and formation of stable emulsion. This method of biosurfactant production can be further scaled up for industrial purpose. 


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Atef M. Ibrahim ◽  
Ragaa A. Hamouda ◽  
Noura El-Ahmady El-Naggar ◽  
Fatma M. Al-Shakankery

AbstractEndoglucanase producing bacteria were isolated from Egyptian soils and the most active bacterial strain was identified as Bacillus subtilis strain Fatma/1. Plackett–Burman statistical design was carried out to assess the effect of seven process variables on endoglucanase production. Carboxymethyl cellulose (CMC), yeast extract and peptone were the most significant variables that enhanced the endoglucanase production and thus were selected for further optimization using face-centered central composite design. The highest yield of endoglucanase (32.37 U/mL) was obtained in run no. 9, using 18 g/L CMC, 8 g/L peptone, 7 g/L yeast extract and 0.1 g/L FeSO4.7H2O. The optimized medium showed about eightfold increase in endoglucanase production compared to the unoptimized medium. The produced crude enzyme was further purified by ammonium sulfate precipitation, then DEAE-Sepharose CL6B column. The purified enzyme was shown to have a molecular weight of 37 kDa. The enzyme showed maximum activity at pH 8.0, temperature of 50 °C, incubation time of 60 min. The half-life time (T1/2) was 139.53 min at 50 °C, while being 82.67 min at 60 °C. Endoglucanase at concentration of 12 U/mL effectively removed 84.61% of biofilm matrix of Pseudomonas aeruginosa with marked reduction in carbohydrate content of the biofilm from 63.4 to 7.9 μg.


2005 ◽  
Vol 187 (3) ◽  
pp. 1192-1195 ◽  
Author(s):  
Hiromi Sato ◽  
Jimmy B. Feix ◽  
Cecilia J. Hillard ◽  
Dara W. Frank

ABSTRACT Recombinant ExoU (rExoU) and yeast extract were used to optimize an in vitro phospholipase assay as a basis for identifying the mechanism for enzyme activation and substrate specificity. Our results support a model in which a eukaryotic protein cofactor or complex facilitates the interaction of rExoU with phospholipid substrates.


2006 ◽  
Vol 50 (9) ◽  
pp. 2990-2995 ◽  
Author(s):  
Xiaofei Jiang ◽  
Zhe Zhang ◽  
Min Li ◽  
Danqiu Zhou ◽  
Feiyi Ruan ◽  
...  

ABSTRACT With the occurrence of extended-spectrum β-lactamases (ESBLs) in Pseudomonas aeruginosa being increasingly reported worldwide, there is a need for a reliable test to detect ESBLs in clinical isolates of P. aeruginosa. In our study, a total of 75 clinical isolates of P. aeruginosa were studied. Nitrocefin tests were performed to detect the β-lactamase enzyme; isoelectric focusing electrophoresis, PCR, and PCR product sequencing were designed to further characterize the contained ESBLs. Various ESBL-screening methods were designed to compare the reliabilities of detecting ESBLs in clinical isolates of P. aeruginosa whose β-lactamases were well characterized. Thirty-four of 36 multidrug-resistant P. aeruginosa clinical isolates were positive for ESBLs. bla VEB-3 was the most prevalent ESBL gene in P. aeruginosa in our study. Among the total of 34 isolates that were considered ESBL producers, 20 strains were positive using conventional combined disk tests and 10 strains were positive using a conventional double-disk synergy test (DDST) with amoxicillin-clavulanate, expanded-spectrum cephalosporins, aztreonam, and cefepime. Modifications of the combined disk test and DDST, which consisted of shorter distances between disks (20 mm instead of 30 mm) and the use of three different plates that contained cloxacillin (200 μg/ml) alone, Phe-Arg β-naphthylamide dihydrochloride (MC-207,110; 20 μg/ml) alone, and both cloxacillin (200 μg/ml) and MC-207,110 (20 μg/ml) increased the sensitivity of the tests to 78.8%, 91.18%, 85.29%, and 97.06%.


2021 ◽  
Author(s):  
Bobby Chettri ◽  
Ningombam Anjana Singha ◽  
Arvind Kumar Singh

Abstract We report kinetics of Assam crude oil degradation by Pseudomonas aeruginosa AKS1 and Bacillus sp. AKS2, both isolated from Assam refinery sediments. The isolates exhibited appreciable degrees of hydrophobicity, emulsification index and biosurfactant production. Crude oil degradation efficiency of isolates was assessed in (1) liquid medium amended with 1% v/v crude oil and (2) microcosm sediments (125 mg crude oil/ 10 g sand). In liquid culture, the biodegradation rate (k) and half-life (t1/2) values were found to be 0.0383 day -1 and 18.09 days for P. aeruginosa AKS1, and 0.0204 day -1 and 33.97 days in case of Bacillus sp. AKS2. In microcosm sand sediments, the estimated biodegradation rate (k) and half-life (t 1/2) values were 0.0138 day -1 and 50 days for P. aeruginosa AKS1, and 0.0113 day -1 and 61.34 days in case of Bacillus sp. AKS2. The level of nutrient treatment in microcosm sand sediment was 125 µg N & 62.5 µg P/g sediment in case of P. aeruginosa AKS1 and 375 µg N & 37.5 µg P/g sediment in case of Bacillus sp. AKS2. In microcosms without inorganic nutrients, biodegradation rate (k) and half-life (t1/2) values were found to be 0.0069 day -1 and 100 days for P. aeruginosa AKS1 and for Bacillus sp. AKS2, the respective values were found to be 0.0046 day -1 and 150.68 days. Our data provides important information for predictive hydrocarbon degradation in liquid medium and contaminated sediments.


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