Extractive Fermentation of Ethanol from Sweet Sorghum Using Vacuum Fractionation Technique: Optimization and Techno-Economic Assessment

Direct extraction of high purity ethanol from fermentation broth was investigated using a vacuum fractionation technique. Batch and repeated-batch extractive fermentation of ethanol were carried out using concentrated sweet sorghum as a carbon source. The effect of product inhibition was reduced by continuous removing ethanol from the fermented broth. About 60 % relative viability was observed in fermented broth with a higher productivity value. Due to the high value of living cells presented in the medium, repeated-batch extractive fermentation was subsequently performed. The ethanol was continuously fractionated out from the system at the average rate of 10.2 g/h with the concentration of approximately 80 wt%. There were 8 cycles of fermentation using only 1 time inoculation. Nevertheless, the calculated ethanol productivity and relative viability for each fermentation cycle were decreased gradually due to the accumulation of toxic substances in fermented broth. The simulation of 200 liters continuous extractive fermentation system using ASPEN PLUS was studied including process optimization and economical consideration. 18.5 liters of ethanol solutions 82 wt% with insignificant amounts of by-product was produced from a 200 liters extractive fermentation system per day. Production cost including raw material and utilities cost was approximately 0.71 €/liter. The economic and systemic performance process were subsequently analyzed, and including that ethanol loss was recovered using a gas scrubber connected to the vapor exiting the venturi tank as well as in the stillage stream. The calculated utility costs after process modification were 0.5 €/liter of ethanol, approximately 30 % of production cost was reduced.

Polimerisasi Eugenol Minyak Daun Cengkeh Hasil Redistilasi, Ekstraksi, dan Fraksinasi Menggunakan Katalis Asam Sulfat Pekat

Polymerization of purified eugenol from clove leaf oil using concentrated sulfuric acid as catalyst has been done in this research. Clove leaf oil was purified by vacuum redistillation, acid-base extraction, and vacuum fractionation to yield eugenol. The eugenol was polymerized with concentrated sulfuric acid in ratio 1: 2. Polyeugenol from eugenol of clove leaf oil resulted from redistillation, extraction, and fractionation is in solid form (yield: 88.14%); from redistillation and extraction is also in solid form (yield: 86.15%); from redistillation clove leaf oil is in gel form (yield: 100.29%). Structure of polyeugenol was determined by infrared spectrophotometer and characterized by thin layer chromatography (TLC). Molecular weight of the product was calculated by viscometry method.DOI: http://dx.doi.org/10.15408/jkv.v0i0.4685