Physical Pretreatment Methods for Improving Microalgae Anaerobic Biodegradability

Olivia Córdova, Fabiana Passos, ROLANDO ARTURO CHAMY MAGGI

Research output: Contribution to journalArticlepeer-review

7 Scopus citations

Abstract

Microalgae may be a potential feedstock for biogas production through anaerobic digestion. However, this process is limited by the hydrolytic stage, due to the complex and resistant microalgae cell wall components. This fact hinders biomass conversion into biogas, demanding the application of pretreatment techniques for inducing cell damage and/or lysis and organic matter solubilisation. In this study, sonication, thermal, ultrasound, homogeneizer, hydrothermal and steam explosion pretreatments were evaluated in different conditions for comparing their effects on anaerobic digestion performance in batch reactors. The results showed that the highest biomass solubilisation values were reached for steam explosion (65–73%) and ultrasound (33–57%). In fact, only applied energies higher than 220 W or temperatures higher than 80 °C induced cell wall lysis in C. sorokiniana. Nonetheless, the highest methane yields were not correlated to biogas production. Thermal hydrolysis and steam explosion showed lower methane yields in respect to non-pretreated biomass, suggesting the presence of toxic compounds that inhibited the biological process. Accordingly, these pretreatment techniques led to a negative energy balance. The best pretreatment method among the ones evaluated was thermal pretreatment, with four times more energy produced that demanded.

Original languageEnglish
Pages (from-to)114-126
Number of pages13
JournalApplied Biochemistry and Biotechnology
Volume185
Issue number1
DOIs
StatePublished - 1 May 2018

Keywords

  • Algae
  • Anaerobic digestion
  • Bioenergy
  • Biogas
  • BMP test
  • Modelling

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