Associated effects of storage and mechanical pre-treatments of microalgae biomass on biomethane yields in anaerobic digestion
메타 데이터
바이오화학분류
바이오정밀화학
연료
논문
Associated effects of storage and mechanical pre-treatments of microalgae biomass on biomethane yields in anaerobic digestion
학술지
Biomass & bioenergy
저자명
Gruber-Brunhumer, M.R.; Jerney, J.; Zohar, E.; Nussbaumer, M.; Hieger, C.; Bromberger, P.; Bochmann, G.; Jirsa, F.; Schagerl, M.; Obbard, J.P.; Fuchs, W.; Drosg, B.
초록
The pre-treatment of microalgae cell walls is known to be a key factor to enhance methane (CH<SUB>4</SUB>) yields during anaerobic digestion. This study investigated the combined effects of two different biomass storage methods and physical pre-treatments on the anaerobic digestion for three different microalgae species. Acutodesmus obliquus, Chlorella vulgaris and Chlorella emersonii were cultivated in 80 L sleevebag photobioreactors (batch mode), and then subjected to different storage (cooling and freezing) and pre-treatment methods prior to anaerobic digestion using the biochemical methane potential (BMP) test. A. obliquus was selected to evaluate pre-treatment methods for further experimentation. Significantly higher CH<SUB>4</SUB> yields of cooled (4 <SUP>o</SUP>C) A. obliquus biomass were achieved through ultrasonication (+53% CH<SUB>4</SUB>) and wet-milling (+51% CH<SUB>4</SUB>). These methods were then applied in follow-up experiments to cooled (4 <SUP>o</SUP>C) biomass of C. emersonii and A. obliquus. Ultrasonication again led to significantly higher CH<SUB>4</SUB> yields for A. obliquus biomass (323 dm<SUP>3</SUP> kg<SUP>-1</SUP> CH<SUB>4</SUB> yield calculated at standard gas conditions of 273 K, and 101.5 kPa per unit volatile solids, +41% CH<SUB>4</SUB>), and C. emersonii biomass (308 dm<SUP>3</SUP> kg<SUP>-1</SUP>; +35% CH<SUB>4</SUB>). In a third experiment series, frozen A. obliquus and C. vulgaris biomass were thawed prior to pre-treatment and BMP-testing. Among all BMP tests, the highest CH<SUB>4</SUB> yields were achieved with untreated, freeze-thawed C. vulgaris biomass (406 dm<SUP>3</SUP> kg<SUP>-1</SUP>); pre-treatment did not enhance CH<SUB>4</SUB> yields for C. vulgaris, but for A. obliquus (ultrasonication +20%). Pre-treatment was more effective for cooled than freeze-thawed microalgal biomass and combined effects acted strain dependently.