Comparison of biogas production from anaerobic digestion of microalgae species belonged to various taxonomic groups

Abstract

tertiolecta to 587 mL CH 4 /g VS for Chlamydomonas reinhardtii (Ward et al. 2014). Diffi culties in anaerobic digestion of microalgae biomass may be attributed to several key factors, such as low concentration of digestible substrate, necessity of pretreatment of algae biomass, unbalanced nutrients in microalgae biomass, the cell wall degradability, the use of limited organic loading rates (OLRs) of the digesters as well as short term storage of biomass (Wirth et al. 2015, Montingelli et al. 2015, Klassen et al. 2015, Ward et al. 2014). It has been also postulated that biogas production cannot be predicted based on the taxonomic group of the algae that are used (Mussgnug et al. 2010), thus experiments must determine the quantity and composition of biogas that can be produced with the individual algal species as a substrate for anaerobic digestion (Ward et al. 2014). The objective of the study was to determine how the use of the three microalgae taxonomic groups of Chlorophyta , Cyanoprokaryota and Bacillariophyceae aff ects the yield and the composition of biogas produced by anaerobic digestion. Abstract: This study investigated the potential of three microalgae taxonomic groups of Chlorophyta , Cyanoprokaryota and Bacillariophyceae for biogas production. Biogas potential was assessed in mesophilic anaerobic digestion batch tests over a period of 20 days. The cumulative biogas yield (CBY) of Chlorophyta and Cyanoprocaryota was respectively 396.21 mL/g Volatile Solids (VS) and 382.45 mL/g VS. Bacillariophyceae digestion showed lower biogas production of 357.07 mL/g VS. The highest cumulative methane yield (CMY) of 241.25 mL CH 4 /g VS was recorded for Cyanoprocaryota biomass, which was signifi cantly higher (p<0.05) than the other two types of microalgae. The highest methane content in biogas of 63.08% was observed with Cyanoprokaryota. Chemical composition of biomass as well as biogas productivity are infl uenced by algal taxonomy.