Bio-hydrogen and Bio-methane from Macro-algae

Bio-hydrogen and Bio-methane from Macro-algae

Researcher: Amita Jacob
T: 353  899845605

Funding Body: Science Foundation Ireland

Programme: MaREI

Project Type: PhD

Period: Jan 2014 – Dec 2017

Project Description:

Macro-algae (seaweed) are considered as third generation biofuel feedstock and are being currently investigated. It scores over terrestrial biomass as it has a higher yield and is lignin free which is generally difficult to degrade via anaerobic digestion. Seaweed can be broadly classified as green, brown and red and each of these contain specific sugars and vary in their volatile solids content. Seaweed also is increasingly being considered as an environmentally friendly method of cleaning waste water runoff from fish farms wherein nitrogenous substances from the excreta of the fish (for example Salmon farms) is sequestered which otherwise is a pollutant, this method known as Integrated multi-trophic aquaculture is gaining renewed interest. 

Anaerobic digestion is a complex microbial process that brings about the degradation of organic substrates present in their complex polymeric nature to simple molecular compounds like methane and carbon dioxide. Several consortia of bacteria (obligate and facultative) and archaea mediate this process in different stages for microbial biomass growth and reproduction. The process of anaerobic digestion can be sub-divided into phases and optimised for each consortium of microbes. In a two phase system the first phase can be used to produce volatile fatty acids (VFA) which can then be fed to a second phase methane reactor. This first phase (known as dark anaerobic fermentation) requires a low pH (5 - 6), a high organic loading rate (ca. 20 kg COD/m3/d), and a short retention time (ca. 2 days). Dark anaerobic fermentation produces a biogas free from methane (methanogens suppressed at pH less than 6) and rich in hydrogen and carbon dioxide. The second phase which is mediated by methanogens produces a biogas rich in methane and carbon dioxide. Hence two energy vectors (hydrogen and methane) can be produced using the two phase method. The aim of this project is to mainly study the factors affecting hydrogen and methane production from macro-algae.

Environmental Research Institute

University College Cork, Lee Road, Cork