Anaerobic co-digestion of microalgal biomass and wheat straw with and without thermo-alkaline pretreatment

Maria Sole Bundo (1, 2) , Cigdem Eskicioglu (2, 3) , Marianna Garfí (2) , Hélène Carrère (1) , Ivet Ferrer (2)

1 LBE - Laboratoire de Biotechnologie de l'Environnement [Narbonne]
2 GEMMA – Group of Environmental Engineering and Microbiology, Department of Civil and Environmental Engineering
3 UBC Bioreactor Technology Group, School of Engineering

This study aimed at analyzing the anaerobic co-digestion of microalgal biomass grown in wastewater and wheat straw. To this end, Biochemical Methane Potential (BMP) tests were carried out testing different substrate proportions (20-80, 50-50 and 80-20%, on a volatile solid basis). In order to improve their biodegradability, the co-digestion of both substrates was also evaluated after applying a thermo-alkaline pretreatment (10% CaO at 75°C for 24h). The highest synergies in degradation rates were observed by adding at least 50% of wheat straw. Therefore, the co-digestion of 50% microalgae - 50% wheat straw was investigated in mesophilic lab-scale reactors. The results showed that the methane yield was increased by 77% with the co-digestion as compared to microalgae mono-digestion, while the pretreatment only increased the methane yield by 15% compared to the untreated mixture. Thus, the anaerobic co-digestion of microalgae and wheat straw was successful even without applying a thermo-alkaline pretreatment.

Mots clés: biogas; C/N ratio; lignocellulosic biomass; thermo-chemical pretreatment; industrial water; wheat straw

Mots clés: biogaz; eaux usées; microalgae; paille de blé; biomasse lignocellulosique; prétraitement thermochimique; potentiel méthane; codigestion

Domaines: Sciences du Vivant [q-bio]

Maria Sole Bundo, Cigdem Eskicioglu, Marianna Garfí, Hélène Carrère, Ivet Ferrer. Anaerobic co-digestion of microalgal biomass and wheat straw with and without thermo-alkaline pretreatment. Bioresource Technology, 2017, 237, pp.89-98. ⟨10.1016/j.biortech.2017.03.151⟩. ⟨hal-01605999⟩