Pretreatment of lignocellulosic biomass can produce inhibitory compounds that are harmful for microorganisms used in the production of biofuels and other chemicals from lignocellulosic sugars. Selective inhibitor removal can be achieved with biodetoxification where microorganisms catabolize the inhibitors without consuming the sugars. We engineered the strictly aerobic Acinetobacter baylyi ADP1 for detoxification of lignocellulosic hydrolysates by removing the gene for glucose dehydrogenase, gcd, which catalyzes the first step in its glucose catabolism. The engineered A. baylyi ADP1 strain was shown to be incapable of consuming the main sugar components of lignocellulosic hydrolysates, i.e., glucose, xylose, and arabinose, but rapidly utilized acetate and formate. Formate was consumed during growth on acetate and by stationary phase cells, and this was enhanced in the presence of a common aromatic inhibitor of lignocellulosic hydrolysates, 4-hydroxybenzoate. The engineered strain tolerated glucose well up to 70 g/l, and the consumption of glucose, xylose, or arabinose was not observed in prolonged cultivations. The engineered strain was applied in removal of oxygen, a gaseous inhibitor of anaerobic fermentations. Co-cultivation with the A. baylyi ADP1 gcd knockout strain under initially aerobic conditions allowed the strictly anaerobic Clostridium butyricum to grow and produce hydrogen (H2) from sugars of the enzymatic rice straw hydrolysate. We demonstrated that the model organism of bacterial genetics and metabolism, A. baylyi ADP1, could be engineered to be an efficient biodetoxification strain of lignocellulosic hydrolysates. Only one gene knockout was required to completely eliminate sugar consumption and the strain could be used in production of anaerobic conditions for the strictly anaerobic hydrogen producer, C. butyricum. Because of these encouraging results, we believe that A. baylyi ADP1 is a promising candidate for the detoxification of lignocellulosic hydrolysates for bioprocesses.

Bacterial cellulose (BC) is a biodegradable polymer that benefits in purity, crystallinity and superior optical, structural and mechanical properties. Such properties facilitate BC to replace the conventional non-biodegradable materials used, for instance, in sensing applications. However, BC production is largely conducted in conventional medium containing model substrates and complex carbon-containing compounds. Aiming towards the production of eco-friendly piezoelectric-responsive BC films, we isolated and characterized a novel bacterial strain affiliated to Komagataeibacter rhaeticus. The K. rhaeticus ENS9a strain synthesized BC in minimal medium containing crude glycerol, generating a titer of 2.9 ± 0.3 g/L BC. This is, to the best of our knowledge, the highest BC titer reported from an unoptimized minimal medium containing crude glycerol. Interestingly, the films prepared from crude glycerol showed normal force and bending mode sensitivities of 6–11 pC/N and 40–71 pC/N, respectively, demonstrating a green platform to address both bioprocess waste valorization and implementation of cellulose-based alternatives for the non-sustainable and non-biodegradable materials, such as fluoropolymers or lead containing piezoceramics, used in sensing applications. In silico genome analysis predicted genes partaking in carbohydrate metabolism, BC biogenesis, and nitrogen fixation/regulation. Graphic