Dekker R F
COPPE, Programa de Engenharia Química, Universidade Federal do Rio de Janeiro, Brasil.
Braz J Med Biol Res. 1989;22(12):1441-56.
The enzymatic hydrolysis of plant carbohydrate polymers is discussed with particular emphasis on lignocellulose. The polysaccharides include starch, inulin, cellulose and the hemicelluloses, i.e., the heteroxylans and glucomannans. Commercial operations exist for the enzymatic hydrolysis of starch and its fermentation into chemicals such as ethanol. Enzymatic hydrolysis of lignocellulose is more complex and the enzymes are rather expensive to produce, which currently precludes the commercial processing of lignocellulosic materials. The bioconversion of lignocellulose consists of 4 process steps: pretreatment, enzyme production, enzymatic saccharification and fermentation. Except for the last step, each of these process steps is discussed. The discussion is highlighted with examples of lignocellulosic waste materials (e.g., sugar cane and a hardwood and softwood sawdust) which are of potential use in a bioconversion process for providing sugar hydrolysates that can serve as fermentation substrates.
本文讨论了植物碳水化合物聚合物的酶促水解，尤其着重于木质纤维素。多糖包括淀粉、菊粉、纤维素和半纤维素，即杂木聚糖和葡甘露聚糖。目前存在淀粉酶促水解及其发酵生产乙醇等化学品的商业运作。木质纤维素的酶促水解更为复杂，且生产酶的成本相当高昂，这目前阻碍了木质纤维素材料的商业化加工。木质纤维素的生物转化包括4个工艺步骤：预处理、酶生产、酶促糖化和发酵。除最后一步外，对这些工艺步骤均进行了讨论。文中以木质纤维素废料（如甘蔗以及硬木和软木锯末）为例进行重点讨论，这些废料在生物转化过程中具有潜在用途，可提供用作发酵底物的糖水解产物。
