Aims: Hyaluronic acid (HA) is a high molecular weight polymer and a major component of mucoid capsule in bacteria and extracellular matrix (ECM) of vertebrate tissue. Due to its unique characteristics, HA is used extensively in medical and cosmetic field. However, because of the exotoxins production from animal tissues extraction and Streptococcus zooepidemicus, HA production by recombinant microorganisms has gained interest. The present study was aimed at cloning of hasA gene in Escherichia coli and optimization of the medium components for HA production. Methodology and results: A fragment of an approximate size of 1.5 kb that encodes the hyaluronan synthase (hasA) gene from S. zooepidemicus ATCC 39920 was amplified by PCR using hasA-specific primers. The hasA gene was ligated into the bacterial expression vector pLbADH and transformed into the expression host, Escherichia coli BL21 strain. Then, genetically engineered E. coli strain BL21 was used for the production of HA by fermentation using different glucose concentration (10-50 g/L) and different IPTG concentration (0.1, 0.5 and 1.0 mM) in shake flask culture. Amongst varying glucose concentrations, results showed that 50 g/L glucose with nutrient rich media containing nitrogen source was able to produce the highest HA concentration (0.115 ± 0.002 g/L). With addition of 1.0 mM IPTG, HA production reached a peak 0.532 ± 0.026 g/L which is around fivefold higher compared to without IPTG. Conclusion, significance and impact of study The hasA gene was cloned from S. zooepidemicus and successfully expressed in recombinant E. coli BL21 cells. This low molecular weight HA is gaining more importance in medical and cosmetic application due to possess pronounced free radical scavenging and antioxidant activities.

Aims: Every year, an estimated 25 million tons of waste oil are produced worldwide, and the generation of waste oil is one of the biggest global environmental problems. The incorporation of oil as a substrate for lipase production has been studied and shown to have a positive impact on its production. Burkholderia sp. is one of the major lipase-producing bacteria with their ability in bioremediation of oil-contaminated soil. This study aims to compare the production of lipase by Burkholderia cenocepacia ST8 using waste cooking oil and unused cooking oil as feedstock. Methodology and results: The effect of different types of waste cooking oil (sunflower oil and palm oil) and concentration (1-3%) of waste cooking oil, agitation speed (100-400 rpm) and initial dissolved oxygen concentration (10-50%) on lipase production by B. cenocepacia ST8 under batch fermentation mode were investigated. The major fatty acids of which had been consumed were determined using gas chromatography. Results showed that 2% (v/v) of single used sunflower cooking oil produced the highest lipase activity of 138.86 U/mL with a productivity of 2.10 U/mL/h; agitation speed of 300 rpm produced the highest lipase activity of 183.56 U/mL with a productivity of 3.06 U/mL/h while 30% initial concentration of dissolved oxygen produced a lipase activity of 176.45 U/mL with a productivity of 2.94 U/mL/h. Oleic acid and linoleic acid were found to be the most consumed by B. cenocepacia ST8 among other fatty acids. Conclusion, significance and impact of study This study shows that 2% (v/v) single used sunflower cooking oil was the better type and optimum concentration of carbon source for the production of lipase by the fermentation of B. cenocepacia under 300 rpm and 30% initial concentration dissolved oxygen. The incorporation of 2% (v/v) single used sunflower cooking oil may be a great alternative to reduce the cost for the production of lipase as well as reducing the amount of waste oil generation.
Lipase ; Burkholderia cenocepacia ; Waste Management ; Biodegradation, Environmental