Abstract
Pretreatment processes were previously carried out with the main objective of recovering cellulose from lignocellulosic material for bioethanol production. Several pretreatment methods were explored in search of an efficient method, which included physiochemical and biological methods and their combination. Two stage pretreatment methods were able to acquire a substantially amount of reducing sugars from lignocellulosic materials. This present study investigates a different pretreatment combination method from the previously reported methods which are anaerobic digestion and acid pretreatment. Ecklonia maxima (E. maxima) as a substrate for this study was subjected to anaerobic digestion as a first process to produce reducing sugars under mesophilic conditions. The reducing sugars produced daily were analyzed using spectrophotometer and high-performance liquid chromatography (HPLC) till day 8 which produced the highest amount of reducing sugars. The obtained reducing sugars were further used in fermentation to investigate bioethanol production. Using gas chromatography-mass spectrometry (GC-MS), the amount of bioethanol produced was found to be 3.55g/l on day 3 of fermentation. The experiment was carried out for the second time using a different batch of E. maxima, focusing on the pretreatment temperature, pretreatment time and acid concentration. After the digestate was acid pretreated, maximum reducing sugars were found to be 346.84 maltose.equiv./ml produced at 80 minutes, 4M and 110℃ conditions. Reducing sugars after acid treatment produced 11.66g/l of bioethanol after being fermented. From the results obtained, it is evident that maximum reducing sugars can be extracted using anaerobic digestion and acid pretreatment subsequently producing bioethanol.