Studio delle comunità microbiche coinvolte nel processo di digestione anaerobica e valorizzazione energetica di biomasse lignocellulosiche di scarto
Author(s)
Mazzurco Miritana, Valentina
Date Issued
June 16, 2017
Type
Doctoral Thesis
Abstract
The aim of the work was to gain deeper insight into microbial interactions of the complex Microbial Community (MC) involved in CH4 production by Anaerobic Digestion (AD). Two batch experiments were carried out in mesophilic conditions (37°C) using wheat straw as substrate. In the 1st experiment two different structured MC were tested to investigate the role of the microbial aggregation on the CH4 productivity. The results showed that the aggregated structure (A) increased the production (42%) when compared to the disaggregated one (D). Both Illumina and FISH techniques showed significant differences in the composition both of A and D inocula, and AP and DP trials.
In the 2nd experiment, the hydrolysis and acidogenesis steps were respectively enhanced by bioaugmentation of the MC of D with: 1) a mix of Anaerobic Ruminal Fungi (ARF) and 2) a fermenting bacteria pool (F210). The best results were obtained when both ARF and F210 were used (1397,2±73,2 ml/l CH4); F210 alone increased the CH4 production but with a lower efficiency (988,3±148,2 ml/l); when only ARF was used, CH4 production was very low (250,8±14,6 ml/l), disproving the effectiveness of their direct interaction with methanogens. Moreover MC analysis (Illumina and FISH) showed very interesting shifts composition along the experimental trial. These results place the ARF at the first step of the AD trophic chain and also show how the equilibrium among the microbial functional component of MC plays a pivotal role.
Additional information
Dottorato di ricerca in Ecologia e gestione delle risorse biologiche
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