A study of the process control and hydrolytic characteristics in a thermophilic hydrogen fermentor fed with starch-rich kitchen waste by using molecular-biological methods and amylase assay
✍ Scribed by Yu-Hsuan Wang; Shiue-Lin Li; I.-Chieh Chen; I.-Cheng Tseng; Sheng-Shung Cheng
- Publisher
- Elsevier Science
- Year
- 2010
- Tongue
- English
- Weight
- 370 KB
- Volume
- 35
- Category
- Article
- ISSN
- 0360-3199
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✦ Synopsis
Starch-rich kitchen waste was chosen as the feedstock in this study, and a 3-L intermittent-continuous stirred tank reactor (I-CSTR) was established. Within 240 days, the maximum average hydrogen production rate of 2.2 L-H 2 L À1 day À1 and the highest average hydrogen yield of 2.1 mmol-H 2 g-COD À1 were both observed in run 3-2, which was operated at an eight-day hydraulic retention time (HRT) and 39 g-COD L À1 day À1 of organic loading rate. According to the analyses of amylase and reducing sugar, the maximum average amylase activity was about 11 U mL À1 in run 1, but the maximum solid carbohydrate hydrolysis rate was about 45% in run 3. Some Michaealis-Menton kinetic parameters, such as K M (17 g L À1 ) and the maximum activity (1.5 U mL À1 ) of the amylase were obtained. The best amylase reacting temperature was 55 C, and the best reacting pH was 4.4 tested with acetate buffer. Twenty-seven operational taxonomic units (OTUs) were selected from this reactor by using a cloning method. According to the data of terminal restricted fragment length polymorphism (T-RFLP) and amylase assay, the OTUs that were related to Thermoanaerobacterium thermosaccharolyticum and Clostridium sp. were in direct proportion to the amylase activity.