ABSTRACT
Abstract Lipases are currently used in food technology for the modification of fats and oils. The thermal stability of lipase is an essential characteristic for this application. This study compares four individual single-step methods (heat treatment, ethanol precipitation, ammonium sulfate precipitation, and size-exclusion chromatography) to enrich lipase concentrations from thermophilic bacterial (Geobacillius stearothermophilus and Anoxybacillus flavithermus) cell lysates. SDS-PAGE and size exclusion chromatography were used to determine the molecular weights of the lipases and the enrichment efficiencies were determined using specific enzyme activities. The molecular weight of G. stearothermophilus lipase was approximately 42 kDa, and approximately 33 kDa for A. flavithermus lipase. For each organism, ethanol precipitation resulted in the highest enrichment fold, followed by ammonium sulfate precipitation, gel filtration and heat treatment respectively. The highest yields for G. stearothermophilus lipase were obtained with ammonium sulfate precipitation, followed by get filtration, and ethanol precipitation respectively. The highest yields for A. flavithermus lipase were obtained from heat treatment followed by ammonium sulfate precipitation, gel filtration and ethanol precipitation respectively. Ethanol precipitation and heat treatment are simple methods for enzyme enrichment from cell lysates and can result in high enzyme yields with moderate enrichment folds compared to complex multi-step purification methods.
ABSTRACT
The purpose of the present study was to screen and identify the lipase-producing microorganisms from various regions of Iran. Samples collected from hot spring, Persian Gulf, desert area and oil-contaminated soil, were analyzed for thermophilic extracellular-lipase producing organisms. Six strains with high activity on rhodamine B plates were selected for chemical identification and further study. Among these isolated bacteria, four strains show higher activity in pH-Stat method at 55 °C. These strains were identified by PCR amplification of 16s rRNA genes using universal primers. Fermentation increased the activity up to 50%. The growth medium, designed for lipase production, increased the activity up to 4.55 folds. The crude supernatant of ZR-5 after fermentation and separation the cells, was lyophilized and the activity was measured. Total activity of this strain was 12 kU/g that shows its potential for industrial uses. Further study is required for purification of enzyme and calculation its specific activity. Immobilization is another approach should be considered.
Subject(s)
Bacteria/enzymology , Bacteria/isolation & purification , Lipase , Bacterial Typing Techniques , Bacteria/classification , Bacteria/genetics , Culture Media/chemistry , DNA, Ribosomal/chemistry , DNA, Ribosomal/genetics , Environmental Microbiology , Enzyme Stability , Hydrogen-Ion Concentration , Iran , Lipase/chemistry , Molecular Sequence Data , /genetics , Sequence Analysis, DNA , TemperatureABSTRACT
The purpose of the present study was to screen and identify the lipase-producing microorganisms from various regions of Iran. Samples collected from hot spring, Persian Gulf, desert area and oil-contaminated soil, were analyzed for thermophilic extracellular-lipase producing organisms. Six strains with high activity on rhodamine B plates were selected for chemical identification and further study. Among these isolated bacteria, four strains show higher activity in pH-Stat method at 55 °C. These strains were identified by PCR amplification of 16s rRNA genes using universal primers. Fermentation increased the activity up to 50%. The growth medium, designed for lipase production, increased the activity up to 4.55 folds. The crude supernatant of ZR-5 after fermentation and separation the cells, was lyophilized and the activity was measured. Total activity of this strain was 12 kU/g that shows its potential for industrial uses. Further study is required for purification of enzyme and calculation its specific activity. Immobilization is another approach should be considered.
Subject(s)
Bacteria/enzymology , Bacteria/isolation & purification , Lipase/metabolism , Bacteria/classification , Bacteria/genetics , Bacterial Typing Techniques , Culture Media/chemistry , DNA, Ribosomal/chemistry , DNA, Ribosomal/genetics , Environmental Microbiology , Enzyme Stability , Hydrogen-Ion Concentration , Iran , Lipase/chemistry , Molecular Sequence Data , RNA, Ribosomal, 16S/genetics , Sequence Analysis, DNA , TemperatureABSTRACT
The purpose of the present study was to screen and identify the lipase-producing microorganisms from various regions of Iran. Samples collected from hot spring, Persian Gulf, desert area and oil-contaminated soil, were analyzed for thermophilic extracellular-lipase producing organisms. Six strains with high activity on rhodamine B plates were selected for chemical identification and further study. Among these isolated bacteria, four strains show higher activity in pH-Stat method at 55 °C. These strains were identified by PCR amplification of 16s rRNA genes using universal primers. Fermentation increased the activity up to 50%. The growth medium, designed for lipase production, increased the activity up to 4.55 folds. The crude supernatant of ZR-5 after fermentation and separation the cells, was lyophilized and the activity was measured. Total activity of this strain was 12 kU/g that shows its potential for industrial uses. Further study is required for purification of enzyme and calculation its specific activity. Immobilization is another approach should be considered.