Lipase Production from a Newly Isolated Aspergillus niger by Solid State Fermentation Using Canola Cake as Substrate

Background: Current studies about lipases production using agro-industrial residues and newly isolated microorganisms aimed at increasing economic attractiveness. Objective: The present study evaluated the lipase production from Aspergillus niger using canola cake as substrate and its extraction and characterization. Methods: Firstly, the microorganism was identified using sequencer ABI PRISM 3100 Genetic Analyzer. After that, experimental design technique was used to determine the variables that can influence the fermentation process, such as: nitrogen supplement and medium moisture; and for the extraction process, the influence of factors as temperature and pH. The lipase was characterized in terms of hydrolytic and esterification activity and specificity, and stability at 10 and -1°C. Results: The obtained results showed that the best condition for the lipase production is 60 wt% of moisture and 2 wt% of urea as supplemental source of nitrogen, and the most appropriate temperature for extraction is 50°C and pH 8.0. In terms of hydrolytic activity, the best conditions were obtained using pH 6.0, 35°C and 32 minutes. The coconut and soybean oil showed the best hydrolytic activity (90 U/g and 74 U/g, respectively), demonstrating that lipases act preferentially in triglycerides of medium and long chain. For the esterification reactions, the higher activity (837 U/g) was obtained using lauric acid as fatty acid and butanol as solvent. Conclusion: In the literature there are few reports about the lipase production from Aspergillus niger using canola cake as substrate. So, the study of the enzyme extraction and characterization after the fermentative process is of extreme relevance.