<正>休哈塔假丝酵母Ｒ（ＣａｎｄｉｄａｓｈｅｈａｔａｅＲ）用于亚硫酸盐制浆废液戊糖、己糖同步酒精发酵时，发酵液ｐＨ值呈规律性变化。引起ｐＨ值变化的原因是发酵过程中酸性非糖还原物被代谢及废液中存在醋酸。废液中已糖对戊糖代谢的抑制可通过调节空气量来解决。还研究了亚硫酸盐制浆废液适宜的发酵条件，在发酵初始ｐＨ５．０～５．５，温度３８±１℃，溶解氧浓度０．９～１．０ｍｇ·Ｌ￣－１的条件下对固形物为１９．９４％的亚硫酸盐制浆废液发酵３４ｈ，废液中戊糖、己糖能同步被酵母利用，糖的利用率为８９．９％，平均每克糖产酒精０．４０ｇ，是理论得率的８３．１％。

When pentoses and hexoses present in spent sulfite liquor (SSL) were simultaneously fermented to ethanol by a Candida shehatae strain, the no-sugar reducing substrates and acetic acid were also consumed, resulting in a pH change profile in which pH was downward in the early stage and upward in the late stage. The repression of hexose catabolite on pentose fermentation could be resolved by controlling the amount of air supply. The best conditions of fermentation were also studied. SSL contaning 19. 94 % solids was neutralized to pH 5. 00～5. 50 followed by fermentation at 38±1℃ for　34 h. With dissolved oxygen concentration at a range of 0. 9～ 1. 0 mg· L~-1. Sugar consumption was 89. 9 %, ethanol yield was 0. 40 g ethanol per g sugar consumed, which is 83. 1 % of the theoretical yield.