ABSTRACT
Solid-state fermentation [also known as solid-state bioprocessing (SSB)] refers to the process where by microbial growth and product formation occurs on the surface of solid materials. This process occurs in the absence of "free" water, where the moisture is absorbed to the solid matrix (Zheng and Shetty, 1999a; Suryanarayan, 2003). Solidstate fermentation (SSF) has a series of advantages over submerged fermentation (SmF) including lower cost, improved product characteristics, higher product yield, easiest product recovery and reduced energy requirement (Cannel and Moo-Young, 1980a, b; Raimbault, 1998; Pandey et al., 2000a; Krishna, 2005). It is of special economic interest for countries with an abundance of agro-industrial residues that are inexpensive substrates for microbial growth (Castilho et al., 2000; Krishna, 2005; Ray et al., 2006), besides preventing disposallinked environmental problems. In recent years, SSF has shown much promise in the development of several bioprocesses and products (Pandey et al., 2000a; Soccol and Vandenberghe, 2003).
