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The transition from a fossil fuel-based economy to a bio-based economy necessitates the exploitation of synergies, scientific innovations and breakthroughs, and step changes in the infrastructure of chemical industry. Sustainable production of chemicals and biopolymers should be dependent entirely on renewable carbon. White biotechnology could provide the necessary tools for the evolution of microbial bioconversion into a key unit operation in future biorefineries. Waste and by-product streams from existing industrial sectors (e.g., food industry, pulp and paper industry, biodiesel and bioethanol production) could be used as renewable resources for both biorefinery development and production of nutrient-complete fermentation feedstocks. This review focuses on the potential of utilizing waste and by-product streams from current industrial activities for the production of chemicals and biopolymers via microbial bioconversion. The first part of this review presents the current status and prospects on fermentative production of important platform chemicals (i.e., selected C2--C6 metabolic products and single cell oil) and biopolymers (i.e., polyhydroxyalkanoates and bacterial cellulose). In the second part, the qualitative and quantitative characteristics of waste and by-product streams from existing industrial sectors are presented. In the third part, the techno-economic aspects of bioconversion processes are critically reviewed. Four case studies showing the potential of case-specific waste and by-product streams for the production of succinic acid and polyhydroxyalkanoates are presented. It is evident that fermentative production of chemicals and biopolymers via refining of waste and by-product streams is a highly important research area with significant prospects for industrial applications. [ABSTRACT FROM AUTHOR]

Up to now, many guest atoms/molecules/ions have been successfully synthesized into graphite to form various compounds. For example, alkali-atom graphite intercalation compounds are verified to reveal stage-n structures, including LiC 6n and LiM 8n [M = K, Rb, and Cs; n = 1, 2, 3; 4]. On the other side, AlCl 4 - -ion/AlCl 4 -molecule compounds are found to show stage-4 and stage-3 structures at room and lower temperatures, respectively. Stage-1 and stage-2 configurations, with the higher intercalant concentrations, cannot be synthesized in experimental laboratories. This might arise from the fact that it is quite difficult to build periodical arrangements along the longitudinal z and transverse directions simultaneously for large ions or molecules. Our work is mainly focused on stage-1 and stage-2 systems in terms of geometric and electronic properties. The critical features, being associated with the atom-dominated energy spectra and wave functions within the specific energy ranges, the active multi-orbital hybridization in distinct chemical bonds, and atom- & orbital-decomposed van Hove singularities, will be thoroughly clarified by the delicate simulations and analyses., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)

We investigate the geometric, electric, and optical properties of two-dimensional honeycomb lattices using first-principles simulations. The main focus of this work is on the similarities and differences in their characteristics, as well as the delicate connection of orbital hybridizations and spin-polarizations with electronic and optical properties. Graphene, silicene, germanene, and their semi-hydrogenated systems, in turn, display sp 2 , sp 2 -sp 3 , and sp 3 s hybridizations. These bonding configurations are critical factors affecting the geometric structure, the electronic band structure, van Hove singularities in density of states, the magnetic configurations, the dielectric functions, and energy loss functions. Furthermore, the meta-stable and stable exciton states are expected to survive in pristine and semi-hydrogenated group IV monolayers, respectively. The theoretical predictions established in this work are important not only for basic science but also for high-tech applications., Competing Interests: The authors declare no competing interests., (This journal is © The Royal Society of Chemistry.)

We perform the electronic and optical properties of the Li 6 PS 5 Cl compound using first-principles calculation. The featured physical and chemical pictures and orbital hybridizations in all Li-S and P-S chemical bonds are clearly exhibited, such as the optimized geometry, the quasi-particle energy spectra, the band-decomposed charge densities, and the van Hove singularities in the density of states. Furthermore, the calculated results of the presence and absence of electron-hole interactions in optical responses are achieved successfully through the dielectric function, the energy loss functions, the absorption coefficients, and the reflectance spectra. The Li 6 PS 5 Cl compound can be useful for extensive applications in all-solid-state batteries and optoelectronic. Our theoretical investigation of Li 6 PS 5 Cl material will encourage further studies to fully comprehend the diverse phenomena for other emerging materials., Competing Interests: The authors declare no conflicts of interest., (This journal is © The Royal Society of Chemistry.)

The rich and unique properties of the stage- n graphite alkali-metal-intercalation compounds are fully investigated by first-principles calculations. According to the main features, the lithium and non-lithium (Na, K, Rb, Cs) systems are quite different from each other in stacking configurations, intercalant alkali-metal-atom concentrations, free conduction electron densities, atom-dominated and (carbon, alkali metal)-co-dominated energy bands, and interlayer charge density distributions. The close relations between the alkali-metal-doped metallic behaviors and the geometric symmetries are clarified through the interlayer atomic interactions. The stage-1 graphite alkali-metal-intercalation compounds possess the highest charge distribution for all stage- n types; moreover, those of the lithium systems are greater than those of the non-lithium systems. The lithium systems also have the largest blue shift of the Fermi level among all alkali metal systems., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)