Renewable biomasses, Metabolic Engineering and Biofuels
Nowadays, cellulose waste biomass (e.g. agro-industrial by-products, municipal solid waste, paper mill sludge) is considered the most attractive substrate for "biorefinery strategies" aimed to produce high-value products (e.g. solvents, fuels, building blocks) by microbial fermentation because of its high abundance, low price and renewability.
However, cellulose is highly recalcitrant to biodegradation and its bioconversion currently requires economically inefficient multistep industrial processes. Our research projects aim to develop suitable microorganisms for one-step conversion (consolidated bioprocessing, CBP) of cellulosic biomass into biofuels (ethanol, butanol) through metabolic pathway engineering genetic techniques (rational engineering and in vivo evolution).
As far as construction of recombinant cellulolytic bacteria is concerned, two paradigms are applied: i) "native cellulolytic strategies", aimed at conferring high-value product properties to natural cellulolytic microorganisms; ii) "recombinant cellulolytic strategies", aimed to confer cellulolytic ability to microorganisms exhibiting high product yields and titers.
Our experimental approach includes:
Detailed study of microbial metabolism by "-omic" techniques (proteomics, transcriptomics, metabolomics) so as to identify key nodes regulating carbon flux Development of gene manipulation tools optimized for microbial strains of interest
Metabolic pathways engineering through "rational" or evolutionary engineering strategy.
Current projects include the construction of: i) a cellulolytic lactic acid bacterium able to efficiently convert cellulose into butanol; ii) Clostridium cellulovorans strains able to convert cellulose into ethanol and/or butanol with high yield, productivity and titers.
2015-2017. Progetto di Ateneo-San Paolo. Metabolic engineering of Clostridium cellulovorans for direct bioconversion (consolidated bio-processing) of cellulosic biomass to ethanol and butanol.