Produzione di bioidrogeno in dark fermentation da scarti dell'industria agroalimentale mediante l'impiego di batteri ipertermofili

This PhD thesis has its subject in the production of bio-hydrogen by dark-fermentation, basing on an anaerobic metabolism of a particular extremophile bacteria of the genus Thermotoga. In this work, carried out within the project Bio-Hydro, using 116mL flasks, the best strain T. neapolitana was selected among four strains tested:. Once the bacterial best candidate has been identified, the optimal value of pH (8.5 at room temperature) for the production of hydrogen has been found. An intense work has been done on the culture medium allowing its minimization making it cost effective for its use in the 19L reactor. In this case glucose was completely replaced with two agro-industrial by-products, the sugar beet molasses and the milk whey. Then micronutrients and vitamins were eliminated. It has been exploited the ability of T. neapolitana to produce biofilm: four different supports were tested. Such tests have allowed to identify Biomax as the best support. Studies have been made on the metabolism of T. neapolitana aimed to identify the inhibitory concentrations of each substrate tested. Also the inhibition by hydrogen and oxygen were investigated. All these tests have given the basic knowledge for the experiments on the 19L reactor. The innovative reactor SPCSTR was entirely designed, developed and built at DICMA: University of Bologna. Batch experiments conducted in SPCSTR gave the opportunity to test this new kind of reactor. At the UR Wageningen (NL), the selection of the best strain among three Caldicellulosisruptor tested was carried out and the best support for the hydrogen production was selected. An innovative reactor CMTB was constructed and tested and continuous experiment was done.