The bioethanol production from lignocellulosic materials is a socially and environmentally well-accepted option; however, its technical and economic feasibility needs to be established. In order to know if the bioethanol production from this feedstock has a potential for implementation, we developed a comparison of 16 process configurations based on four pretreatment methods and six conversion options. Indexes that relate to energy consumption, amount of bioethanol produced, water consumption, and final bioethanol composition were used to compare the processing options. Seven alternatives were selected for further analysis with the implementation of a separation process. It was found that the process based on dilute acid pretreatment and enzymatic hydrolysis and cofermentation combination shows the best economic potential. On the other hand, the cellulose hydrolysis based on an enzymatic process showed the best energy efficiency, but the final economic incentive for industrial implementation depends strongly on a fairly low enzyme cost.
The present work aimed to design a separation process for 2-phenylethanol (2-PEA) produced by whey fermentation and to evaluate its economic potential. The separation sequence consisted of a liquid–liquid extraction column followed by two distillation columns for 2-PEA purification and solvent recovery. In addition, the use of ethyl acetate as a solvent for the extraction process was analyzed. The results, aided by the Aspen Plus v.10 process simulator, showed that 2-PEA can be separated with a purity of 96% by weight. The operating cost of the process, estimated at USD 22.70 per kilogram, shows that the separation alternative developed in this work has a high economic potential. The use of ethyl acetate as a solvent was found to efficiently remove 2-PEA from the fermentation mixture. From a process safety analysis point of view, the use of a bioprocess safety index developed in this work identified the separation process sections that could require special attention as part of the safety engineering stage of the process implementation.
In some fermentation systems, whey components (lactose, proteins and minerals) can produce isopentyl acetate (IA). An analysis of the best conditions for IA production with Kluyveromyces marxianus was developed in this work. The experiment design was two-factor and three-level design based on a response surface methodology (RSM) using Design-Expert® software. The analysis of anomeric protons by nuclear magnetic resonance (1H-NMR) showed 81.25% of β lactose content. This characteristic favored the production of IA. The maximum output (Mp) of IA, determined by gas chromatography, was 9.52 g/L (p < 0.05). The central composite design (CCD) was used to perform the factor analysis. Results showed that concentrations of 0.03 (g/L) ammonium sulphate and 0.3 (v/v) of isoamyl alcohol are the best conditions for a maximum rate of IA production. The production of IA can reduce the discharge of whey, allowing its reuse and revaluation.
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