Alam Md Zahangir, Muyibi Suleyman A, Wahid Rosmaziah
Bioenvironmental Engineering Research Unit, Department of Biotechnology Engineering, Faculty of Engineering, International Islamic University Malaysia, Gombak, 50728 Kuala Lumpur, Malaysia.
Bioresour Technol. 2008 Jul;99(11):4709-16. doi: 10.1016/j.biortech.2007.09.072. Epub 2007 Nov 5.
A two-level fractional factorial design (FFD) was used to determine the effects of six factors, i.e. substrate (domestic wastewater sludge - DWS) and co-substrate concentration (wheat flour - WF), temperature, initial pH, inoculum size and agitation rate on the production of cellulase enzyme by Trichoderma harzianum in liquid state bioconversion. On statistical analysis of the results from the experimental studies, optimum process conditions were found to be temperature 32.5 degrees C, substrate concentration (DWS) 0.75% (w/w), co-substrate (WF) concentration 2% (w/w), initial pH 5, inoculum size 2% (v/w) and agitation 175 rpm. Analysis of variance (ANOVA) showed a high coefficient of determination (R2) of 0.975. Cellulase activity reached 10.2 FPU/ml at day 3 during the fermentation process which indicated about 1.5-fold increase in production compared to the cellulase activity obtained from the results of design of experiment (6.9 FPU/ml). Biodegradation of DWS was also evaluated to verify the efficiency of the bioconversion process as a waste management method.
采用两级析因设计（FFD）来确定六个因素的影响，即底物（生活污水污泥 - DWS）和共底物浓度（小麦粉 - WF）、温度、初始pH值、接种量和搅拌速率对哈茨木霉在液态生物转化中产生纤维素酶的影响。通过对实验研究结果进行统计分析，发现最佳工艺条件为温度32.5摄氏度、底物浓度（DWS）0.75%（w/w）、共底物（WF）浓度2%（w/w）、初始pH值5、接种量2%（v/w）和搅拌速度175转/分钟。方差分析（ANOVA）显示决定系数（R2）高达0.975。在发酵过程的第3天，纤维素酶活性达到10.2 FPU/ml，这表明与实验设计结果（6.9 FPU/ml）相比，产量提高了约1.5倍。还对DWS的生物降解进行了评估，以验证作为一种废物管理方法的生物转化过程的效率。
