Nutrients and COD removal of swine wastewater with an isolated microalgal strain Neochloris aquatica CL-M1 accumulating high carbohydrate content used for biobutanol production

• Published in: Bioresource technology 2017-10, Vol.242, p.7-14
• Main Authors: Wang, Yue, Ho, Shih-Hsin, Cheng, Chieh-Lun, Nagarajan, Dillirani, Guo, Wan-Qian, Lin, Chiayi, Li, Shuangfei, Ren, Nanqi, Chang, Jo-Shu
• Format: Article
• Language: English
• Subjects: Animals; biobutanol; Biomass; biomass production; butanol; Butanol fermentation; Carbohydrate; carbohydrate content; Carbohydrates; chemical oxygen demand; Chlorophyta; COD/nutrient removal; feedstocks; fermentation; glucose; light intensity; Microalgae; Neochloris; Neochloris aquatica CL-M1; Swine; Swine wastewater; temperature; Waste Water; wastewater; xylose
• ISSN: 0960-8524; 1873-2976
• DOI: 10.1016/j.biortech.2017.03.122

•Carbohydrate-rich microalga Neochloris aquatica CL-M1 was grown in swine wastewater.•Effect of temp., light and N/P ratio on nutrient removal/cell growth was studied.•81.7% COD removal and 96.2% NH3-N removal was achieved with the microalgal growth.•Biomass conc. and carbohydrate content reached 6.10gL−1 and 50.46%, respectively.•The pretreated algal biomass was used to produce butanol with good efficiency. In this study, a carbohydrate-rich microalga Neochloris aquatica CL-M1 was adapted to grow in swine wastewater. The effects of cultivation conditions (i.e., temperature, light intensity or N/P ratio) on COD/nutrients removal and carbohydrate-rich biomass production were investigated. The results indicate that the highest COD removal (81.7%) and NH3-N removal (96.2%) was achieved at 150µmolm−2s−1 light intensity, 25°C and N/P ratio=1.5/1. The highest biomass concentration and carbohydrate content was 6.10gL−1 and 50.46%, respectively, when N/P ratio=5/1. The resulting carbohydrate-rich microalgal biomass was pretreated and used as a feedstock for butanol fermentation. With the initial sugar concentration of 48.7gL−1 glucose and 3.4gL−1 xylose in the pretreated biomass, the butanol concentration, yield, and productivity were 12.0gL−1, 0.60molmol−1 sugar, and 0.89gL−1h−1, respectively, indicating the high potential of using Neochloris aquatica CL-M1 for butanol fermentation.