Using bio-adhesive and bio-inert surfaces to maximize biogas production and influence microbial growth in anaerobic digesters

Doctoral thesis English OPEN
Dobrzanska, Dorota A.
  • Subject: TD | QD | QH

The optimisation of biogas digesters is crucial for further development of sustainable energy sources. In this research, an integrative approach was taken to understanding how this problem can be addressed including: seeking a better understanding of protein – surface interactions on the molecular level; larger scale experiments to screen the best materials for use in laboratory scale anaerobic digesters to influence microbial growth and biofilm development as well as analysis of farm-scale data using the ADM1 multiparameter model.\ud \ud The laboratory-scale experiments were undertaken to develop surfaces suitable for studying microbial immobilization. This work, currently using tertiary amines, amine oxides and comparator oligoethylene glycol studies the adsorption of two classic model proteins: lysozyme and fibrinogen using quartz crystal microbalance methods and represents important steps for selecting and exploring surface – protein interactions. The data showed that tertiary amine oxides are more resistant to nonspecific protein adsorption than the corresponding tertiary amines.\ud \ud Heat modified polyurethane foam was used to explore biofilm and planktonic phase microbial populations in a fixed film biogas reactor.. After four weeks the foam was analysed by ‘next generation’ 454-sequencing to identify the influence of the supporting materials on microbial population residing in anaerobic digesters. The results revealed that Spirochaetes, Methanobacterium and Methanocorpusculum associated themselves with heat modified polyurethane foams.\ud \ud Finally, data from a farm-scale anaerobic digester (volatile fatty acid concentration, temperature and pH) have been gathered and entered into the ADM1 model, developed by the mathematical modelling group from Lund University, to mimic the behaviour of a laboratory scale 1.5 l reactor and identify improved conditions for methanogens stability.\ud \ud The combination of approaches described above will allow the identification of which parameters will enhance the operation of anaerobic digesters and has identified surfaces that promote adhesion of particular Bacteria and Archaea in order to increase biogas production.
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