Anaerobic co-digestion of multiple agricultural residues to enhance biogas production in southern Italy.

To valorize agricultural wastes and byproducts in southern Italy, anaerobic co-digestion of six feedstocks (citrus pulp, olive pomace, cattle manure, poultry litter, whey, and corn silage) was studied to produce biogas for renewable energy generation. Both batch and semi-continuous co-digestion approaches were adopted to carry out the investigation. The feedstocks were mixed at different percentages according to their availabilities in southern Italy. The batch anaerobic co-digestion demonstrated that six studied feedstock mixtures generated an average of 239 mL CH4/g VS loading without significant difference between each other, which concluded that the feedstock mixtures can be used for biogas production. Considering the feedstock availability of citrus pulp and olive pomace in Sicily, three feedstock mixtures with the highest volatile solids concentration of citrus pulp (42% citrus pulp, 17% corn silage, 4% cattle manure, 8% poultry litter, and 18% whey; 34% citrus pulp, 8% olive pomace, 17% corn silage, 4% cattle manure, 8% poultry litter, and 18% whey; and 25% citrus pulp, 16% olive pomace, 17% corn silage, 4% cattle manure, 8% poultry litter, and 18% whey, respectively) were selected to run the semi-continuous anaerobic digestion. Under the stabilized culture condition, the feed mixture with 42% citrus pulp, 17% corn silage, 4% cattle manure, 8% poultry litter, and 18% whey presented the best biogas production (231 L methane/kg VS loading/day). The corresponding mass and energy balance concluded that all three tested feedstock mixtures have positive net energy outputs (1.5, 0.9, and 1.2 kWh-e/kg dry feedstock mixture, respectively).

2-Methyltetrahydrofuran and cyclopentylmethylether: two green solvents for efficient purification of membrane proteins like FhuA.

ß-Barrel shaped membrane proteins are attractive hosts for hybrid catalysts in which reactions are controlled through space. Production and extraction of ß-barrel shaped membrane proteins in gram scale is challenging due to their hydrophobicity. Solvent mixtures such as chloroform/methanol (CM) are widely used for membrane protein extraction but toxicity and mutagenicity were reported in several cases. 2-Methyltetrahydrofuran (2-MeTHF) and cyclopentylmethylether (CPME) are two green (reduction of solvent-related environmental damage in chemical production) and potentially efficient solvents for membrane protein purification. On the example of the ferric hydroxamate uptake protein component A (FhuA) a 4-Step method was developed to provide gram amounts of highly purified FhuA: cell disruption (Step 1), removal of membrane protein impurities with n-octyl-poly-oxyethylene (oPOE) (Step 2), dissolution of membranes and FhuA precipitation (Step 3), and refolding using urea and dialysis with polyethylene-polyethyleneglycol (PE-PEG; Step 4) resulted in high FhuA purity (95% 2-MeTHF, 80% CPME; 70mg FhuA per liter fermenter broth). Structural integrity of FhuA protein was confirmed by circular dichroism (CD) and a translocation functionality assay.

Asymmetric reduction of ketones with recombinant E. coli whole cells in neat substrates.

The asymmetric reduction of ketones is performed by using lyophilized whole cells in neat substrates with defined water activity (a(w)). Ketones and alcohols prone to be unstable in aqueous media can now be converted via biocatalysis.