Department of Bioengineering, Faculty of Engineering, Ege University, 35100 Bornova-Izmir, Turkey.
Bioresour Technol. 2012 Sep;120:52-9. doi: 10.1016/j.biortech.2012.06.057. Epub 2012 Jun 26.
The extracts of Stevia rebaudiana are marketed as dietary supplements and utilized as natural sweetening agent in food products. Subsequent to extraction on industrial scale, large quantities of solid wastes are produced. The aim of this study was to investigate the bioconversion efficiency of supercritical CO(2) extracted S. rebaudiana residues. Therefore, leaves were extracted with supercritical CO(2) and ethanol mixture in order to obtain glycosides, then the raffinate phase was hydrolyzed by both dilute acid and various concentrations of cellulase and β-glucosidase cocktail. The maximum yield of reducing sugars reached 25.67 g/L under the optimal conditions of enzyme pretreatment, whereas 32.00 g/L was reached by consecutive enzymatic and acid hydrolyses. Bioethanol yield (20 g/L, 2.0% inoculum, 2 days) based on the sugar consumed was 45.55% corresponding to a productivity of 0.19 kg/m(3)h which demonstrates challenges to be utilized as a potential feedstock for the production of bioethanol.
甜菊叶提取物作为膳食补充剂销售，并在食品产品中用作天然甜味剂。在工业规模提取之后，会产生大量的固体废弃物。本研究的目的是研究超临界 CO(2)提取的甜菊叶残渣的生物转化效率。因此，用超临界 CO(2)和乙醇混合物提取叶片以获得糖苷，然后用稀酸和不同浓度的纤维素酶和β-葡萄糖苷酶混合物水解萃余相。在酶预处理的最佳条件下，还原糖的最大产率达到 25.67 g/L，而连续酶解和酸解则达到 32.00 g/L。基于消耗的糖，生物乙醇的产率（20 g/L、2.0%接种物、2 天）为 45.55%，相应的生产率为 0.19 kg/m(3)h，表明其用作生物乙醇生产的潜在原料存在挑战。
