Generally, the economic viability of microbial biomass production processes is limited by the cost of the fermentation medium, which can account for almost 30% of the total production cost. The use of alternative, low-cost and widely available raw materials becomes thus of special interest when producing products obtained from industrial microbial processes (Karatay et al., 2010).
Sugarcane molasses(SCM)is a complex mixture of sugars(containing sucrose, glucose and fructose about 50% w/w) arising from sugar processing and it is obtained as a waste product of the sugar industry. Because of its availability and low cost (10% of pure sugar cost) it is considered a promising carbon substrate. Indeed it has been used as substrate to produce lipids (Johnson et al., 1995) and carotenoids (Bhosale and Gadre, 2001) by yeasts.
Another low-cost carbon substrate rich in sugars that can be used in media formulation is the carob pulp syrup (CPS). The carob tree (Ceratonia siliqua L.) is a leguminous plant, which has been widely cultivated in southern european countries for years. The seeds of carob (10% of the fruit dry weight) produce 12% of the world market of gum and are widely used in the food industry. The pulp (the remaining 90% of the fruit dry weight) contains high content of sugar (sucrose, glucose and fructose) and tannins and low content of protein and fat, which limits its application as animal feed. The easily extractable sugars from the pulp makes this material eligible for the production of syrups that can be used as substrate for fermentation (Mendes et al., 2007). So far, this carob industry by-product has never been used to produce lipids and/or carotenoids by yeasts.