Omega-3 fatty acids and astaxanthin produced by chlorella vulgaris and haematococcus pluvialis cultivated in chicken manure medium

Abstract

Chicken manure contains a high concentration of nutrients such as nitrogen and phosphate, which can be used to replace commercially available medium for growth of microalgae. Cultivating microalgae by using chicken manure as the nutrients can reduce the cost of cultivation and also increase the quality of fish pellet in aquaculture systems. This research was conducted to study the growth of Chlorella vulgaris and Haematococcus pluvialis in different concentrations of chicken manure on the growth of C. vulgaris and H. pluvialis. The concentration of omega-3 fatty acids in C. vulgaris and astaxanthin in H. pluvialis were determined by cultivating C. vulgaris and H. pluvialis in Bold Basal medium and Rudic medium respectively, and compared with chicken manure medium (CM). 50% of CM concentration was considered the best chicken manure concentration to replace commercial medium in C. vulgaris cultivation, although the Bold Basal Medium and 50% of CM has a comparable specific growth rate of 0.178 day-1 and 0.512 day-1 respectively. However, it will be much cost effective to use a waste product with high nutrients, i.e., CM instead of commercial medium to grow the microalgae. In H. pluvialis cultivation, the highest specific growth rate was obtained in 50% of CM and 40% of CM with 0.554 day-1 and 0.528 day-1, respectively. For omega-3 fatty acid, the highest concentration was obtained in 14.8% C. vulgaris in 10% of CM due to depletion of nitrogen, which causes the increase of fatty acid production in the microalgae. For astaxanthin production, H. pluvialis grown in 50% of CM gave highest concentration of astaxanthin (0.082 mg/mL). The increase in astaxanthin was due to low concentration of phosphorus in the growth medium.