Fermentation strategies for the production of lipase by an indigenous isolate Burkholderia sp. C20

Statistical optimization of cultural medium composition of thermoalkalophilic lipase produced by a chemically induced mutant strain of Bacillus atrophaeus FSHM2

Extremophilic microbial derived lipases have been widely applied in different biotechnological processes due to their resistance to harsh conditions such as high salt concentration, elevated temperature, and extreme acidic or alkaline pH. The present study was designed to overproduce the halophilic, thermoalkalophilic lipase of Bacillus atrophaeus FSHM2 through chemically induced random mutagenesis and optimization of cultural medium components assisted by statistical experimental design. At first, improvement of lipase production ability of B. atrophaeus FSHM2 was performed through exposure of the wild bacterial strain to ethidium bromide for 5-90 min to obtain a suitable mutant of lipase producer (designated as EB-5, 4301.1 U/l). Afterwards, Plackett-Burman experimental design augmented to D-optimal design was employed to optimize medium components (olive oil, maltose, glucose, sucrose, tryptone, urea, (NH₄)₂SO₄, NaCl, CaCl₂, and ZnSO₄) for lipase production by the EB-5 mutant. A maximum lipase production of 14,824.3 U/l was predicted in the optimum medium containing 5% of olive oil, 0.5% of glucose, 0.5% of sucrose, 2% of maltose, 2.5 g/l of yeast extract, 1.75 g/l of urea, 1.75 g/l of (NH₄)₂SO₄, 2.5 g/l of tryptone, 2 g/l of NaCl, 1 g/l of CaCl₂, and 1 g/l of ZnSO₄. A mean value of 14,773 ± 576.9 U/l of lipase was acquired from real experiments.

Optimization of the production and characterization of lipase from Candida rugosa and Geotrichum candidum in soybean molasses by submerged fermentation

This present work describes the production and biochemical characterization of lipase by Candida rugosa and Geotrichum candidum in a culture supplemented with soybean molasses. After optimizing the fermentation times for both microorganisms, the effects of changing the soybean molasses concentration, the fermentative medium pH and the fermentation temperature were evaluated using the Central Composite Planning. When soybean molasses was used at a concentration of 200 g/L at 27 ± 1 °C and pH 3.5, the lipolytic activity measured in the broth was 12.3 U/mL after 12 h for C. rugosa and 11.48 U/mL after 24 h for G. candidum. The molecular masses were 38.3 kDa to G. candidum lipase and 59.7 kDa to C. rugosa lipase, determined by SDS-PAGE. The lipase from both microorganisms exhibited maximal hydrolytic activity at a temperature of 40 °C and were inhibited at pH 10.0. Using different concentration of p-nitrophenylbutyrate (p-NPB), the kinetic parameters were calculated, as follows: the Km of lipase from G. candidum was 465.44 μM and the Vmax 0.384 μmol/min; the Km and Vmax of lipase from C. rugosa were 129.21 μM and 0.034 μmol/min, respectively. Lipases activity were increased by metallic ions Mg(2+) and Na(+) and inhibited by metallic ion Cu(3+).

Optimization and partial purification of a high-activity lipase synthesized by a newly isolated Acinetobacter from offshore waters of the Caspian Sea under solid-state fermentation

A new aerobic mesophilic bacterium was isolated from the southern coastal waters of the Caspian Sea which substantially produced an extracellular lipase in solid-state fermentation using milled coriander seeds (MCS) as support substrate.