Department of Bioprocess Technology, Faculty of Biotechnology and Biomolecular Sciences, Universiti Putra Malaysia, 43400 UPM, Serdang, Selangor, Malaysia.
Department of Process and Food Engineering, Faculty of Engineering, Universiti Putra Malaysia, 43400 UPM, Serdang, Selangor, Malaysia.
Waste Manag. 2017 Sep;67:95-105. doi: 10.1016/j.wasman.2017.05.017. Epub 2017 May 17.
In Malaysia, the amount of food waste produced is estimated at approximately 70% of total municipal solid waste generated and characterised by high amount of carbohydrate polymers such as starch, cellulose, and sugars. Considering the beneficial organic fraction contained, its utilization as an alternative substrate specifically for bioethanol production has receiving more attention. However, the sustainable production of bioethanol from food waste is linked to the efficient pretreatment needed for higher production of fermentable sugar prior to fermentation. In this work, a modified sequential acid-enzymatic hydrolysis process has been developed to produce high concentration of fermentable sugars; glucose, sucrose, fructose and maltose. The process started with hydrothermal and dilute acid pretreatment by hydrochloric acid (HCl) and sulphuric acid (HSO) which aim to degrade larger molecules of polysaccharide before accessible for further steps of enzymatic hydrolysis by glucoamylase. A kinetic model is proposed to perform an optimal hydrolysis for obtaining high fermentable sugars. The results suggested that a significant increase in fermentable sugar production (2.04-folds) with conversion efficiency of 86.8% was observed via sequential acid-enzymatic pretreatment as compared to dilute acid pretreatment (∼42.4% conversion efficiency). The bioethanol production by Saccharomyces cerevisiae utilizing fermentable sugar obtained shows ethanol yield of 0.42g/g with conversion efficiency of 85.38% based on the theoretical yield was achieved. The finding indicates that food waste can be considered as a promising substrate for bioethanol production.
在马来西亚，产生的食物垃圾量估计约占总城市固体废物的 70%，其特点是含有大量碳水化合物聚合物，如淀粉、纤维素和糖。考虑到其中有益的有机成分，将其作为生物乙醇生产的替代基质的利用受到了更多关注。然而，从食物垃圾中可持续生产生物乙醇与高效预处理有关，需要在发酵前生产出更多可发酵糖。在这项工作中，开发了一种改良的顺序酸酶水解工艺，以生产高浓度的可发酵糖，包括葡萄糖、蔗糖、果糖和麦芽糖。该工艺首先采用盐酸（HCl）和硫酸（HSO）进行水热和稀酸预处理，旨在降解多糖的较大分子，然后进行糖化酶进一步的酶水解。提出了一个动力学模型来进行最佳水解，以获得高可发酵糖。结果表明，与稀酸预处理相比（转化率约为 42.4%），顺序酸酶预处理可显著提高可发酵糖的产量（提高 2.04 倍），转化率达到 86.8%。利用获得的可发酵糖通过酿酒酵母进行生物乙醇生产，实现了 0.42g/g 的乙醇产率和 85.38%的转化率，基于理论产率。研究结果表明，食物垃圾可以被视为生物乙醇生产的有前途的底物。
