Advantage of Acid Sulfite Cooking as Processes of Bioethanol Production

Abstract

From the standpoints of biorefinering processes, Japanese larch (Larix leptolepis) wood, acacia (Acacia meamsii) wood, and bamboo (Phyllostachys pubescens) stem were cooked using the magnesium base/acid sulfite cooking method, and the dissolution behavior of carbohydrate in spent sulfite liquor (SSL) was studied. It was found that glucose dissolves rapidly into SSL immediately after sufficient removal of lignin from the pulp. Cellulose more rapidly dissolved as glucose into SSL at the later stage of cooking than at the initial stage. In addition, it was shown that larch mannan and acacia xylan dissolve as monosaccharides and oligosaccharides during the initial stage of cooking, and that both the hydrolysis of oligosaccharides and the decomposition of monosaccharides in SSL proceeded with increasing cooking time. The amount of enzyme adsorbed to residual lignin in enzyme-treated pulp was measured by pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS). The enzyme-treated acid sulfite pulp (SP) absorbed cellulase as 30∼80 FPU on 1 g of lignin. It has a much lower value than soda-anthraquinone (AQ) pulp enzyme-treated.