Microbial fermentation production of valuable phytochemicals may be colocated (onsite, integral use of materials or energy streams) with starch — or lignocellulose-based bioenergy processes, to benefit from locally produced, inexpensive fermentable sugars (intermediates or by-products of bioenergy processes) (Thomsen et al., 2006). In principle, all microbial fermen­tations for biochemicals production may be run on sugars converted from starch, sugarcane or lignocellu — lose in various bioenergy processes, to yield chemicals like surfactants, polyols or organic acids (Choi et al., 2007; Aalford and Morel, 2006; Mapari et al., 2005). For instance, X. dendrorhous can be grown on cellulases- digested pine and produce carotenoids (Chattopadhyay et al., 2008), and Serratia marcescens can be grown on processed cassava waste to produce prodigiosin (Casullo de Araujo et al., 2010).

Utilization of Phytochemical Production By-Products for Bioenergy

Production of valuable phytochemicals (such as those for therapeutic, cosmetic, dietary or agricultural uses) from either wild-type or transgenic plants generates lignocellulosic by-products. Such materials might serve as feedstocks for (onsite) bioenergy production. This might add value, reduce waste, and enhance raw mate­rial or energy use efficiency. For instance, the woody residues from vinblastine or vincristine production in C. roseus (Braz-Filho, 1999) or other natural products production (Simard et al., 2012), or the citrus peel resi­dues from furanocoumarins, flavonoid glycosides, poly- methoxylated flavones, triterpenoids, limonoids or peel oil extraction (Manthey, 2012), have potential as bio­energy feedstocks.

Phytochemical production has focused mainly on therapeutic, dietary or cosmetic agents from specific fruits, flowers, nuts, vegetables, or other plant sources. In comparison, less attention has been paid on phyto­chemicals coproduction in current or future bioenergy processes. Integral coproductions of biofuels, biochem­icals, phytochemicals and other valuable materials are imperative for highly efficient and viable bioenergy and biorefinery processes (Huang and Ramaswamy, 2012). In some cases, relatively simple combinations or colocations of existing bioenergy and phytochemi­cals processes may suffice to coproduce biofuels, biochemicals and phytochemicals. In other cases, new production technology or process engineering may need to be developed. To maximize the economy of raw materials and energy utilization and minimize the carbon footprint, bioenergy processes will evolve into more comprehensive biorefineries in which the coproduction of industrial phytochemicals plays an important role.