Biofuel co-products as livestock feed - Opportunities and challenges

Micro-algae for fuel and use of spent biomass for feed and for other uses 441fertilizer and conditioner. Thus production and utilization ofalgal biomass with net energy gain in the process withoutwaste generation would be desirable for the sustainableexploitation of the technology for energy needs.Several companies worldwide are working on algaebasedbiofuels. Though cost effective, viable technologyhas not yet been developed, the approaches suggested inthis review for utilizing spent biomass for feed and all otherdifferent fractions in a biorefinery manner would go a longway in making the process economic.KNOWLEDGE GAPS AND FUTURE RESEARCHNEEDS There is a continuing need to screen the vast biodiversityof micro-organisms to identify high yielding strains. Further genetic improvement of potential strains forachieving higher biomass and metabolite yield and subsequentscale-up.. It is important to devise culture methodologies based onthe nature of the alga. Efficient utilization of seawater, waste water, flue gasesand various carbon dioxide sources for enhanced productionof biomass. Utilization of wind and solar power for culture agitationand harvesting. Drying of biomass employing solar drying systems. Achieving the least energy losses for net energy gain. Developing bio-refinery approaches with minimal energyinputs and effective utilization of all by-products andco-products. To develop integrated systems of feed and food productionfor use of biomass in a meaningful manner. Algal biomass derived feeds and feed supplements needto be developed for augmenting animal products, aquacultureand the poultry industry, thus adding value toexisting technologies. Utilization of marginal land for algal biomass cultivation. Exploring setting up of production plants at the sea surfaceor in coastal areas.Table 11 lists some of the potential process developmentsfor utilization coupled to integration of technologywith renewable energy inputs for net energy gain.CONCLUSIONSThe energy demands of the world coupled with deterioratingenvironmental conditions have high lighted theneed for eco-friendly measures for sustainable solutions.In this regard, algal biotechnology utilizing the vast biodiversityavailable for production of bio-energy moleculesis already recognized as a promising area for meeting thedual demands for energy and respect for the environment.Having realized the importance of photo synthetic carbonfixation for the production of energy-rich molecules, thedevelopment of technologies to produce biomass on amassive scale would need research and developmentalinputs for evaluating viable technology alternatives. Theidentification of algal forms, their cultivation and utilizationwould go a long way to realize the desired objectives.Approaches to achieving net energy gain in a sustainableand eco-friendly manner need to be developed andadopted. The current trends and future prospects touchedon in this review could provide directions for advances ineffective utilization of algal biotechnology for fuel, food,feed and chemicals.ACKNOWLEDGEMENTSGAR and RS thank the Council of Scientific IndustrialResearch, Department of Science and Technology,Department of Biotechnology, Government of India; theGTZ programme of Germany; and the industries who havesupported algal biotechnology research at CFTRI, Mysore.BIBLIOGRAPHYAnderson, G.A., Anil, K. & Schipull, M.A. 2002.Photobioreactor Design. Paper No. MBSK02-216, presentedat the 2002 ASAE/CSAE North-Central IntersectionalMeeting. Society for Engineering in Agricultural, Food andBiological Systems.TABLE 11Process innovation and renewable energy utilization for net energy gain and utilization of co-productsProcess stepsEmploying organisms with high growth rate in addition tohigh product or metabolite productionAdoption of open bioreactorsMixing of cultureHarvesting of the cultureRecycling of the water back to the inoculum ponds.Adoption of closed bioreactorsDrying of algal biomassExtraction of constituents (lipids and hydrocarbons) andutilization of spent biomassAdoption of innovative measures and use of renewable energyResponsiveness to environmental conditions such as stress factors for increaseyields needs to be explored.Media optimization, culture conditions.Windmill driven.Through sedimentation. Adoption of proper gradient for separation of thebiomass.Windmill driven.Use of solar radiation for providing the light source and mixing of culturethrough windmill-driven peristaltic pumps,Solar drying system.Biorefinery approach.