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168 The Journal of the Royal Institute of Thailand Volume III - 2011 168 Cassava Industry in Thailand: Prospects Figure 4. Effective use of cassava crop in a biorefinery. Cassava-based biomaterials With a rising concern for environmental impact, finding alternatives to substitute petrochemical products has gained much attention throughout the world. Instead of exploiting oil/petroleum-based materials, attempts have been made to develop the use of sustainable and renewable resources by bioprocess. These bio-products have high potential for future growth in various applications including films, packaging, fibres, adhesives and super-absorbents according to their biodegradability attributes. When used as biomaterials, starch can be used in two major forms, i.e. as monomer and polymer. A glucose monomer obtained from starch hydrolysis, preferably by enzyme process, is a good substrate for microbial fermentation. A spectrum of fermented products can be generated depending on microbial types. Some significant ones are lactic acid for making polylactic acid (PLA), succinic acid for making polybutylene succinate, propanediol and polyhydroxybutyrate (PHB). When used in polymer form, starch can be used in the form of granular or gelatinized starch. The major advantage of using starch is low cost, high quantity, renewable and biodegradable. However, starch is more hydrophilic and has less mechanical properties than conventional petroleum- 160-170_mac9 5/3/12, 11:43 PM 168