Toxic algal bloom used to cultivate freshwater algae with biofuel potential

Scientists in India have investigated ways in which toxic algal bloom can be used for cultivating Chlorella pyrenoidosa, a freshwater algae increasingly considered a candidate for biodiesel production.

Although algae are naturally occurring, excessive amounts of nutrients in a body of water can lead to rapid multiplication and the formation of algal blooms covering the surface. Some of these algae produce toxins which are harmful to humans and wildlife, meaning they can have a disruptive effect on marine environments and lead to a decrease in fish populations.

Scientists from the Indian Institute of Technology, Roorkee deployed toxic algal bloom as a copious, low cost nutrient source for cultivating Chlorella pyrenoidosa. Various pre-treatment methods, using combinations of acid/alkali and autoclave/microwave were tested for preparing hydrolysates, and compared with minimal media (BG-11).

It was discovered that acid autoclave hydrolysis produced the maximum nitrogen, phosphate and carbon content, substantially boosting the growth of the microalgal cells.

“The microalga grown in this media also showed enhanced lipid content (43.2%) and lipid productivity (188 mg/L/d) as compared to BG-11 (19.42 mg/L/d),” the authors write in the abstract to their study.

“The biochemical composition showed 1.6-fold declines in protein while 1.27 folds in carbohydrate content as compared to BG-11. The fatty acid profile revealed the presence of C14-C22 with increased amount of monounsaturated fatty acids as compared to BG-11.”

Chlorella pyrenoidosa has long been used in traditional Chinese medicines. In recent years, a range of studies have looked at it as a potentially strong candidate for the production of algae biofuels.

 

The team's results will be published in the October edition of the journal Bioresource Technology