【作者】 舒勤；

【导师】 夏黎明；

【作者基本信息】 浙江大学 ， 生物化工， 2004， 硕士

【摘要】 由细菌产生的纤维素酶其最适反应pH值通常为中性到碱性，近年来，这类酶制剂在纸浆脱油墨和洗涤剂等工业领域中得到了成功的应用，对于这类酶制剂的研究具有重要的学术意义和实际应用价值。 本文选用嗜碱性芽孢杆菌Bacillus sp.AC-2发酵生产纤维素酶，在摇瓶条件下对Bacillus sp.AC-2的产酶工艺进行了研究，包括种子培养时间、接种量、初始pH值、培养温度、碳源、C／N、氮源、无机盐和表面活性剂等。采用优化后的培养基及培养条件，发酵44小时，Bacillus sp.AC-2所产纤维素酶在pH7.0和pH9.5条件下分别为111.25U／mL和76.04U／mL。 进一步在3.7L发酵罐中进行产酶研究。确立了适宜的通气量和搅拌速度分别为0.2vvm和200rpm；在最佳发酵条件下，中性纤维素酶和碱性纤维素酶产量达到了136.77U／mL和93.48U／mL。这一结果已达到同类文献报道的先进水平，显示了良好的应用前景。 对Bacillus sp.AC-2纤维素酶的酶学性质研究表明：该酶除了主要具有内切-β-葡聚糖酶(CMC酶)活性外，还有一定的淀粉酶活力和少量的滤纸酶活力，未测出纤维二糖酶活力。Bacillus sp.AC-2纤维素酶的最佳反应温度和pH值分别为60℃和7.0；在pH6.0～10.0、温度低于70℃条件下比较稳定；不同的金属离子对酶活具有一定的激活或者抑制作用。 Bacillus sp.AC-2纤维素酶在纸浆酶法脱墨方面展示了良好的应用前景，经它处理过的纸浆不仅白度好，而且对纤维的破坏程度也小；酶用量以100U／g为适宜；吐温80和适当的机械作用可以提高酶法脱墨效果。初步实验表明，Bacillussp.AC-2纤维素酶在洗涤剂工业中具有巨大的应用潜力，当酶的添加量为2％、水洗时间1小时，该酶能有效地提高洗衣粉对污布的水洗能力。 芽孢杆菌所产的纤维素酶具有重要的工业应用价值，目前对这类酶制剂的工业化生产国内尚属空白。本论文的研究结果在学术上和应用中都具有重要意义。更多还原

【Abstract】 Cellulase production using an alkalophilic strain Bacillus sp. AC-2, the enzymatic characteristics and the applications in pulp deinking & textile biofinishing were studied in the thesis.Fermentation conditions for the cellulase producing were studied in shaking flasks by Bacillus sp. AC-2, including inoculum age, inoculum volume, initial pH value, fermentation temperature, carbon sources, ratio of C/N, nitrogen sources and surface active agent, etc. Under the optimal conditions, the CMCase activities at pH7.0 and pH9.5 reached 111.25 U/mL and 76.04 u/ml respectively in 44 hours.The cellulase production was carried out in a 3.7L fermentor. It was found that the optimal fermentation conditions were 0.2vvm and 200rpm. A high cellulase activity was obtained (136.77 U/mL at pH 7.0 and 93.48U/mL at pH9.5).The studies on the enzymatic characteristic showed that Bacillus sp. AC-2 cellulase mainly had CMCase activity with a little activity of amylase and FPA. The enzyme was stable under pH 6.0-10.0 and below 70℃; The optimum temperature and pH value were 60℃ and 7.0, but it also showed a high activity at pH9.5. Metal ions had different effects to the enzymatic activity.The cellulase from Bacillus sp. AC-2 showed a good application potential in waste paper deinldng and detergent industry. The research work in this dissertation was meaningful both in theoretical research and practical application.更多还原