Biorefinery bioconversions

The present chapter focuses on process options integrated in a biorefinery scheme that should yield bio-products at a more competitive market price and quality. Although bioconversions are essential steps to derive the platform molecules that are used subsequently for catalytic transformations, only chemo-catalytic process will be examined. Selected examples of catalytic conversions illustrating different process options will be given. 

One can envisage the future production of liquid fuels and commodity chemicals in a biorefinery Biomass is first subjected to extraction to remove waxes and essential oils. Various options are possible for conversion of the remaining biofeedstock, which consists primarily of lignocellulose. It can be converted to synthesis gas (CO + H2) by gasification, for example, and subsequently to methanol. Alternatively, it can be subjected to hydrothermal upgrading (HTU), affording liquid biofuels from which known transport fuels and bulk chemicals can be produced. An appealing option is bioconversion to ethanol by fermentation. The ethanol can be used directly as a liquid fuel and/or converted to ethylene as a base chemical. Such a hiorefinery is depicted in Fig. 8.1. 

Menon V, Rao M. (2012). Trends in bioconversion of lignocellulose biofuels, platform chemicals biorefinery concept. Prog Energy Combust Sci, 38, 522-550. 

Future research incentives on the development of biorefineries should focus on all aspects of the process regarding upstream processing (ie, evaluation of various raiewable raw materials and conversion strategies), bioconversion for SCO production, downstream conversion of SCO into biodiesel or other fuels, and generation of co-products through valorization of cmde glycerol or other side/waste streams. Furthermore, it is essential to evaluate the economic viability and sustainability of industrial-scale, SCO-based biodiesel production. 

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