Evaluation of extracellular amylolytic enzyme activity in Chlorella sorokiniana via an experimental screening design
摘要
The production of microalgae presents a great biotechnological opportunity for industry, such as for Chlorella sorokiniana, a microorganism with high biotechnological potential that has been shown to be capable of releasing extracellular enzymes of biotechnological and economic interest. The objective of this research was to evaluate the cell growth and extracellular amylolytic activity of C. sorokiniana via a Plackett–Burman experimental design and to evaluate the growth factors and kinetic growth constants. The experimental results and the statistical analysis revealed that the conditions with the greatest effect on cell growth and amylolytic activity were high temperature (37 °C) and a long photoperiod (16 h). These factors were ranked by their impact as follows: photoperiod > temperature > nitrate concentration for cell growth and temperature > photoperiod for enzymatic activity. Under these conditions, the maximum cell growth achieved was 489 × 106 cells/mL (8.69 Log10 cells/mL), and the highest amylolytic activity recorded was 1,281.5 U/mL. The best results for the calculated kinetic growth constants were µ = 0.021/h, td = 4.505 h, δ = 0.22/h, YX/S = 5.307 g biomass/g NaNO3 and YP/S = 0.100 g protein/g NaNO3. The control of growth factors, including temperature, photoperiod, and nitrate concentration, allows C. sorokiniana to achieve good amylolytic activity and biomass production, which is favorable for biotechnological applications.
Graphical abstract