Austrian Centre of Industrial Biotechnology (ACIB) Develops Advanced Biofuels without Food Use
(Melodika.net) …Biofuels of the 2nd generation are made of agricultural waste – from wood chips, straw or specially cultivated “energy crops”. The Austrian competence centre acib (Austrian Centre of Industrial Biotechnology) has found ways to make these renewable sugar resources available for industry and for the production of biofuels.
The enzymes that are used are called cellulases. They can cleave cellulose and hemicellulose – both components of wood (besides lignin) – into small sugar molecules, explains Professor Christian Kubicek of the Technical University of Vienna. In the framework of the center of excellence acib, he works together with researchers in Graz and at an industrial partner’s site on the access of new industrial sugars from renewable resources. The enzymes work like choppers, says Professor Anton Glieder, scientific director of acib, “the long cellulose chains are transported through the enzymes. Thereby, the enzyme cuts small sugar molecules off the comparatively huge cellulose chain, until the whole cellulose is digested into smaller sugars.” The best enzymes for the process are produced using the fungus Trichoderma reesei, which normally grows on decaying wood residues. In the Styrian project “MacroFun” at Graz University of Technology the fungal enzymes are be improved by using the yeast Pichia pastoris to make the “molecular shredder” more robust, declares Glieder.
Admittedly, the general procedure is still extensive, says Kubicek. The plant remains or “energy crops” such as flower stalk grass (Miscanthus) or switchgrass (Panicum virgatum) must first be “unlocked” to separate the lignin and make the cellulose accessible. Then specially designed cellulases come into play and cleave the long cellulose chains into small sugars. These are finally converted – similar to the alcoholic fermentation in wine – from yeast to bioethanol, which can then be used for biofuels. The great advantage of this method: food remains completely unaffected and the carbon footprint looks a lot better. READ MORE