Growth study of organic solvent tolerant bacteria (OSTB) in solvent waste mixture of semiconductor industry

@#Aims:Increasing of organic solvent waste contributed as one of the most critical environmental problems. Huge amount of solvents hasbeen applied in the industrial process, but it is not followed by a good waste treatment. Up to our knowledge only a few studieshas been conducted in applying the biological treatment on the solvent waste mixtures specifically by Gram’s positive organic solvent tolerant bacteria (OSTB). The study aims to identify the ability of OSTB survival in solvent waste mixture of the semiconductor industry in comparison to synthetic organic solvent by OSTB inoculation.Methodology and results:Strain of OSTB named as Bacillus subtilis, BSIAs was applied in the study. The growth of this OSTB in different concentration of synthetic solvent isopropyl alcohol (IPA) and in actual solvent waste mixture consists of IPA was monitored and measured. There are three different concentrations (v/v) of synthetic solvent IPA was used as a media that are 20%, 10% and 5% for testing the growth of B.subtilisBSIAs. The 5% concentration of IPA was suitable for B.subtilisBSIAs growth. After 14 hof growth, distillation process was used to separate the remaining solvent from the mixture. It was found that, the volume after biological treatment was reduced by 1 mL from the initial volume of solvent before the biological treatment. This OSTB also utilized solvent in 1% concentration of real solvent waste mixture within 120 h.Conclusion, significance and impact of study:As a conclusion, the findings reveal that the strain of Gram-positive B.subtilis,BSIAs has the ability to utilize synthetic organic solvent (IPA)and the solvent waste mixture from the semiconductor industry as their carbon sources. The selected OSTB can be considered as bio-agents in the industrial waste management pertaining to solvent waste problems thru green technology approaches.

A new isolate of thermophilic and organic solvent tolerant bacteria for lipase production using basal medium of palm kernel cake 80-87

@#Aims: This research focused on the selection of potential strains especially bacteria that can grow effectively in palm kernel cake (PKC) and produce high amount of thermostable and solvent tolerant (TS-OST) lipase. The work involved the exploration of renewable PKC as potential fermentation medium for discovery to novel TS-OST lipase that would have excellent tolerance and activity in presence of organic solvents with high temperatures for industrial applications.Methodology and results: Using palm kernel cake (PKC) as source of thermophilic bacteria, 53 bacterial strains were found survived at temperature 65 °C. However, after subcultured several times, only 17 strains were found as pure thermophilic strains. Preliminary screening both qualitative and quantitative was performed to all 17 potential thermophilic bacterial strains and showed that only 11 purified thermophilic strains are lipase producer. Strain PKC-P1 produced highest enzyme activity (11.13 U/g), followed by PKC-P13 and PKC-C9. The lowest enzymeactivity was lipase produced byPKC-C10 (0.76U/g). Strain PKC-P1 has been classified as Gram negative bacteria and identified as Bacillus smithiistrain PKC_P1.Conclusion, significance and impact of study: PKC as a by-product of oil palm industry consistsof many nutrients that can give benefits towards industry and can be utilized in order to produce enzymes like lipases. From these results, it could be concluded that this lipase stable at temperature 65 °C and pH 7 and may be a potential candidate to be used in a variety of biotechnological applications. This finding revealed that a bacterial strain obtained from oil-rich environment which is PKC through isolation process has potential as a source of more economical enzyme to be applied in biotechnology industr

Process optimization for production and purification of a thermostable, organic solvent tolerant lipase from Acinetobacter sp. AU07

ABSTRACT The purpose of this study was to isolate, purify and optimize the production conditions of an organic solvent tolerant and thermostable lipase from Acinetobacter sp. AU07 isolated from distillery waste. The lipase production was optimized by response surface methodology, and a maximum production of 14.5 U/mL was observed at 30 ºC and pH 7, using a 0.5% (v/v) inoculum, 2% (v/v) castor oil (inducer), and agitation 150 rpm. The optimized conditions from the shake flask experiments were validated in a 3 L lab scale bioreactor, and the lipase production increased to 48 U/mL. The enzyme was purified by ammonium sulfate precipitation and ion exchange chromatography and the overall yield was 36%. SDS-PAGE indicated a molecular weight of 45 kDa for the purified protein, and Matrix assisted laser desorption/ionization time of flight analysis of the purified lipase showed sequence similarity with GDSL family of lipases. The optimum temperature and pH for activity of the enzyme was found to be 50 ºC and 8.0, respectively. The lipase was completely inhibited by phenylmethylsulfonyl fluoride but minimal inhibition was observed when incubated with ethylenediaminetetraacetic acid and dithiothreitol. The enzyme was stable in the presence of non-polar hydrophobic solvents. Detergents like SDS inhibited enzyme activity; however, there was minimal loss of enzyme activity when incubated with hydrogen peroxide, Tween 80 and Triton X-100. The kinetic constants (Km and Vmax) revealed that the hydrolytic activity of the lipase was specific to moderate chain fatty acid esters. The Vmax, Km and Vmax/Km ratio of the enzyme were 16.98 U/mg, 0.51 mM, and 33.29, respectively when 4-nitrophenyl palmitate was used as a substrate.

Lipase production and growth modeling of a novel thermophilic bacterium: aneurinibacillus thermoaerophilus strain AFNA

Aneurinibacillus thermoaerophilus strain AFNA as a novel isolated extracellular thermostable organic solvent tolerant lipase producing bacterium was employed in the present study. The lipase production of strain AFNA and its correlation with bacterial growth was studied via a modeling assessment by response surface methodology (RSM) and artificial neural network (ANN) techniques. The best achieved models were multilayer full feed forward incremental back propagation network and modified cubic response surface model (mRSM) using backward elimination. The highest lipase specific activity (13.1 Umg-1) and bacterial growth (OD600 = 3.0) were obtained at technically similar: growth temperature (53 and 53ºC), inoculum size (2.6 and 3.0 percent), agitation rate (118 and 115 rpm) and initial pH (7.0 and 7.2) but different medium volume (139 and 87 ml) and incubation period (48 and 38 hrs), respectively. In addition, the importance of effective parameters on the bacterial growth and lipase production was studied where pH and inoculum size were the most and the least effective factors, respectively. Significant correlation between lipase production and bacterial growth was observed when Bivariate correlation was employed to analyse the data. As a conclusion, lipase production was the result of a synergistic combination of effective parameters interactions and these parameters were in equilibrium.

Effect of Alkanes on the Production of a Solvent-stable Extracellular Protease by the Organic Solvent Tolerant Bacterium Bacillus licheniformis YP1 / 微生物学通报

In this paper, the effect of 5% (V/V) n-alkanes (e.g, n-Heptane, n-Octane, n-Decane, n-Dodecanen-Tetradecane and n-Hexadecane) on the growth and protease production of organic-solvent-tolerant- bacte-rium Bacillus licheniformis YP1 was studied. 5%(V/V) n-alkanes had no effect on the stability of YP1 prote-ase. 5% (V/V) n-alkanes had no notable influence on the yield of strain YP1 but dramatically affected theprotease production. The presence of n-Heptane, n-Octane and n-Decane deeply repressed the protease pro-duction; however n-Dodecane, n-Tetradecane and n-Hexadecane enhanced the protease production promi-nencely. The concentration of n-Tetradecane (1%-8%, V/V) had a direct ration with the protease production.The detailed experiments showed that the notable increase of protease activity appeared at the late logarithmof cultivation compared with the blank. The cell shape of YP1 strain remarkably decreased when grown inthe presence of n-Tetradecane. This is the first report about the effect of n-alkanes on the protease productionby the solvent tolerant bacterium.