Thermo-molded biocomposite from cassava starch, natural fibers and lignin associated by laccase-mediator system

Treatment of cellulose fibers and lignin by laccase-mediator system was conducted to enhance the binding efficiency of natural fibers and lignin compounds into cassava starch composite matrix. Violuric acid (VA) was tested for its effect as a mediator for laccase treatment. Influence of different fiber, lignin and water contents of biocomposite was statistically investigated. The results showed that adding 15% (w/w) fibers into biocomposite at 44% (w/w) water content increased flexural strength and modulus for 4 times compared with the control. A combination of fibers + VA gave the greatest enhancement of modulus for 1140% and flexural strength for 375.8% as much as neat starch biocomposite. The presence of fibers, lignin and VA as mediator for laccase treatment substantially enhanced water resistance of starch biocomposite detected by a change in water drop contact angle on biocomposite surface.