Optimization of cell culture and cell disruption processes to enhance the production of thermophilic cellulase FnCel5A in E.coli using response surface methodology

Response Surface Methodology for Optimization Membrane Disruption Using Thermolysis in Lipase Lk2 and Lk3

Lk2 and Lk3 were thermostable recombinant lipase and highly expressed in Escherichia coli BL21 (DE3). However, Lk2 and Lk3 accumulated as an inclusion body. To further characterize both recombinant lipases, the soluble enzyme must be obtained first. This study aimed to optimize the disruption of the cell membrane in order to obtain soluble and active lipases. The effects of temperature lysis, pH, and SDS concentration on lipolytic activity Lk2 and Lk3 were investigated using a three-factor Box-Behnken design response surface methods. The optimum condition for the temperature variables at 50°C, pH 8, and 0.34% SDS which gave a lipolytic activity of 0.9 U for Lk2. Meanwhile, Lk3 lipolytic activity of 0.9 U obtained at the temperature of 50°C, pH 8, and 0.1% SDS. This result showed efficient one-step membrane disruption methods using thermolysis with addition of a low concentration of detergent at pH 8. The methods used were effective and applicable in the production of active and soluble thermostable recombinant lipase.

Combination of Analytical and Statistical Methods in Order to Optimize Antibacterial Activity of Clary Sage Supercritical Fluid Extracts

The extraction of clary sage (Salvia sclarea L.) using supercritical carbon dioxide (SC-CO2) was systematically studied by using thin layer chromatography-direct bioautography (TLC-DB) and response surface methodology (RSM). The three parameters temperature, pressure, and cosolvent ratio were optimized for the maximum antibacterial activity of clary sage extracts against Pseudomonas aeruginosa (P. aeruginosa) and methicillin-resistant Staphylococcus aureus (MRSA). The highest inhibition zone was 7.51 mm for P. aeruginosa and 7.57 mm for MRSA. According to RSM analysis, the predicted optimum extraction parameters are 18.6 MPa pressure, 40 °C temperature, and 2% ethanol (EtOH) ratio. The combination of this analytical and statistical method allows saving time, money, and instrument runtime in the optimization of essential oil composition, which is tailored to a specific task and could be useful on any kind of herbs in a wide range of use from perfume manufacturing to the food industry.

Optimized soluble expression of a novel endoglucanase from Burkholderia pyrrocinia in Escherichia coli

Burkholderia pyrrocinia B1213, a novel microbe isolated from a Baijiu-producing environment, displayed strong cellulolytic activity on agar plates with glucan as the carbon source and had an activity of 674.5 U/mL after culturing with barley. Genome annotation of B. pyrrocinia identificated a single endoglucanase (EG)-encoding gene, designated as BpEG01790. The endoglucanase BpEG01790 shows 98.28% sequence similarity with an endo-β-1,4-glucanase (EC 3.2.1.4) from Burkholderia stabilis belonging to glycoside hydrolase family 8 (GH8). The gene BpEG01790 has an open reading frame of 1218 bp encoding a 406 amino acid (AA) residue protein (43.0 kDa) with a 40-AA signal peptide. BpEG01790 was successfully cloned into pET28a( +) with and without the signal peptide; however, attempts to overexpress this protein in Escherichia coli BL21(DE3) cells using this expression system failed. BpEG01790 was also cloned into the pCold TF vector. Active BpEG01790 was successfully overexpressed with or without the signal peptide using the pCold TF vector expression system and E. coli BL21 (DE3) cells. Overexpression of recombinant BpEG01790 without the signal peptide was higher compared with the construct that included the signal peptide. Optimization of culture conditions improved the enzyme activity by 12.5-fold. This is the first report describing the heterologous soluble overexpression of an EG belonging to GH8 from B. pyrrocinia using TF as a molecular chaperone.