Research Article
Gene Drekeke Iyovo, Guocheng D
Abstract
Poultry manure (PM) was decomposed under high and low aeration-agitations and the digestates were supplemented in mixotrophic cultivation of microalga Chlorella vulgaris. High aerobic decomposition was recommended for faster mineralization. The study was conducted to find out the effect of poultry manure digestate (PMD) on cell biomass and lipid yield in C. vulagris. The cultivation were conducted ‘with’ (single and two-stage feeding strategy) and ‘without’ PMD feeding. Cultivation ‘without’ PMD at 120 h, dry cell weight (DCW) of 8.2g/L was reached, by 180 h, lipid yield of 2.1 g/L (45%) was reached. In single-stage of adding varied PMD, at 120 h, DCWs of 8.48, 9.39 and 10.45 g/L were achieved for PMD of 20, 30 and 40 ml/L, respectively. By 180 h, lipid contents were 45, 43 and 40% giving yields of 2.4, 2 and 1.8 g/L, respectively. In twostage feeding (0-120 h and 120-180 h), at 120 h, DCWs were similar to single-stage but improved when supplementing with 2 g/L glucose reaching DCW of 12.6, 13.14 and 14 g/L achieving lipid yields of 2.9, 3.8 and 4.9 g/L, respectively, after 180 h. The addition of glucose seems to assist nitrogen depletion which in turn resulted in rapid increase in cellular lipid. It was obvious that addition of glucose at stationary phase maybe a novel method to improve lipid yields. The algal biomass PMD dependent accumulation showed that PM is an attractive waste which means that PM is potential waste for algae biofuels.