ABSTRACT
Among the non-conventional processes for renewable energy production including pyrolysis, solar, thermal, hydro and wind power, biological production of energy-containing gaseous and liquid fuels from biomass represents an important part of the solution to addressing future energy needs. Methane gas production is considered a most favored, simple and economical method of
INTRODUCTION
Corresponding Author
production of energy from agro-industrial, horticultural and food processing wastes (Lane, 1979; Nand, 1994; Verstraete and Vandevivere, 1999). Biological production of hydrogen gas, a very clean fuel, has vast potential. However, unlike methane production where the technology is available now, biological hydrogen production is much more complex and the technology is at an initial stage of development. With regard to production of liquid biofuels, processes for production of bioethanol are available. However, for conversion of waste products typically containing mixed hexose and pentose sugars and with significant proportions of the sugar associated with polymeric substances, including lignocellulose and cellulose that are difficult to degrade, advances in the technology are still required. There is also considerable interest in using anaerobic processes for production of acetone-butanol, processes that were exploited during the First and Second World War, but have been discontinued because of their lack of economic competitiveness. New biotechnology strategies have potential to improve these processes. A different approach to generation of liquid fuels from biomass does not directly require a microbial step, but rather involves physico-chemical-or bio-transformation of oil from oil seed crops into diesel-like fuels, described as biodiesel. These seed oil resources are available in many regions of the world, where there are no or limited petroleum oil resources.
