Hideno Akihiro, Ogbonna James C, Aoyagi Hideki, Tanaka Hideo
Graduate School of Life and Environmental Sciences, University of Tsukuba, 1-1-1 Tennoudai, Tsukuba, Ibaraki 305-8572, Japan.
J Biosci Bioeng. 2007 Apr;103(4):311-7. doi: 10.1263/jbb.103.311.
The feasibility of using loofa sponge for immobilization of cellulase-producing microorganisms was investigated by acetylating loofa sponge. Acetylation was achieved by autoclaving process of loofa sponge immersed in acetic anhydride at various temperatures for various times. The degree of acetylation, as inferred by the weight percentage gain (WPG), was enhanced by increasing both temperature and the duration of acetylation. The acetylation of a piece of loofa sponge in an autoclave at 120 degrees C for 20 min resulted in a WPG of about 8%, which was sufficient to protect the loofa sponge against cellulose degradation. The acetylated loofa sponge prepared under this condition was not decomposed by commercial cellulase and its structure was maintained for more than 720 h during repeated-batch treatments with commercial cellulase. A flocculating yeast (Saccharomyces cerevisiae IR-2) and a fungus (Trichoderma reesei QM9414) were successfully immobilized in the acetylated loofa sponge. In each case, the percentage of immobilized cells was as high as that obtained using nonacetylated loofa sponge. Acetylation had no adverse effects on cell growth and immobilization of T. reesei QM9414, as well as on cell growth and ethanol production by S. cerevisiae IR-2. T. reesei QM9414 immobilized on an acetylated loofa sponge was successfully used for repeated-batch cellulase production from commercial cellulose powder. Although the acetylated loofa sponge showed a slight weight loss, it was not disintegrated by activated sludge. The results obtained in this study showed that acetylated loofa sponge is suitable as an immobilization carrier for bioprocesses involving cellulase.
通过对丝瓜海绵进行乙酰化处理，研究了其用于固定产纤维素酶微生物的可行性。乙酰化是通过将丝瓜海绵浸泡在乙酸酐中，在不同温度下高压灭菌不同时间来实现的。通过重量增加百分比（WPG）推断，乙酰化程度随着温度和乙酰化时间的增加而提高。在120℃高压灭菌20分钟的一块丝瓜海绵的乙酰化导致WPG约为8%，这足以保护丝瓜海绵免受纤维素降解。在此条件下制备的乙酰化丝瓜海绵不会被商业纤维素酶分解，并且在与商业纤维素酶的重复批次处理过程中其结构保持超过720小时。一种絮凝酵母（酿酒酵母IR-2）和一种真菌（里氏木霉QM9414）成功固定在乙酰化丝瓜海绵中。在每种情况下，固定化细胞的百分比与使用未乙酰化丝瓜海绵时获得的百分比一样高。乙酰化对里氏木霉QM9414的细胞生长和固定化以及酿酒酵母IR-2的细胞生长和乙醇生产没有不利影响。固定在乙酰化丝瓜海绵上的里氏木霉QM9414成功用于从商业纤维素粉末中重复批次生产纤维素酶。虽然乙酰化丝瓜海绵显示出轻微的重量损失，但它不会被活性污泥分解。本研究获得的结果表明，乙酰化丝瓜海绵适合作为涉及纤维素酶的生物过程的固定化载体。
