Studio del processo di produzione biologica d’idrogeno mediante Dark fermentation
Author(s)
Patriarca, Chiara
Date Issued
June 12, 2013
Type
Doctoral Thesis
Abstract
The environmental impact of energy and reserves depends on increasing human-related activities. Waste material accumulation causes irregular allocation modifying biogeochemical cycle flow and creating pollution.
Hydrogen is considered one of the most promising candidates as a substitute for fossil fuel, because it is clean, renewable and has a high energy yield. Furthermore the use of biomass waste to produce bio-hydrogen can fulfill the goal of waste reduction by avoiding the impact of its disposal into the environment.
The aim of the present study was to investigate the feasibility of bio-hydrogen production by dark fermentation using agro-industrial wastes (cheese whey, manure, glycerol and silage sorgum). Furthermore considering dark fermentation as integral part of anaerobic digestion the aim was also to improve the overall methane yield during the final anaerobic digestion phase.
The microbial hydrogen-producing consortium isolated from marine lake sediment has been identified as suitable microbial pool able to produce high hydrogen yield (1,68 mol H2/mol glu) as compared to literature (2 mole maximum theorethical yield) under the same experimental conditions. The present survey also investigated different type of wastes deriving from agro-industrial and zootechnical farms. Through this study, wastes were evaluated individually and by codigestion biomasses; all discard products were able of producing hydrogen through dark fermentation. Furthermore sterilization treatment increased of two/three time production yield probably avoiding non sporogenic hydrogen consuming bacteria present as indigenous flora in the biomasses. Hydrogen-producing mixed acid pathway has been investigated as the dominant pathway, that resulted consistent with hydrogen-producing bacteria identified during this research (Enterobacter e Clostridium). This study confirmed and further demonstrated that by adding hydrogen production bacteria to the natural methane production consortium it is possible to obtain a methane production improvement between 31 and 48%. This confirms the hydrogen production key-role even during anaerobic digestion process.
Additional information
Dottorato di ricerca in Ecologia e gestione delle risorse biologiche
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