have performed a detail economic analysis of the production of Penicillium restrictum lipase in both SmF and SSF. They found that for a production scale of 100 m 3 lipase concentrate per year, total capital investment
needed for SmF was 78% higher than that needed for SSF. Also, SSF unitary product cost was 47% lower than the selling price. These studies pointed out that the great advantage of SSF processes is the extremely cheap
raw material used as main substrate. Therefore, SSF is certainly a good way of utilising nutrient rich solid wastes as a substrate. Both food and agricultural wastes are produced in huge amounts and since they are rich in carbohydrates and other nutrients, they can serve as a substrate for the production of bulk chemicals and enzymes using SSF technique.