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Biological Process for Butanol Production
Published in Jay J. Cheng, Biomass to Renewable Energy Processes, 2017
Maurycy Daroch, Jian-Hang Zhu, Fangxiao Yang
Perstraction is a process that can address some of the drawbacks of liquid–liquid extraction, including cell toxicity, emulsion formation, extraction solvent loss, and rag layer formation (i.e., cell accumulation at the interphase) (Ezeji et al., 2007). During perstracion separation process a porous membrane is placed between two phases to separate them. The membrane contactor provides surface area to exchange butanol between the two immiscible phases of broth and extractant. As there is no direct contact between the two phases, extractant toxicity, phase dispersion, emulsion, and rag layer formation are drastically reduced or eliminated. In such a system, butanol would diffuse preferentially across the membrane, while other components, including fermentation intermediates (e.g., acetic and butyric acids), could be retained in the aqueous phase (Qureshi et al., 2005). The total mass transport largely depends on the diffusion rate of butanol across the membrane (Ezeji et al., 2007).
Butanol from Renewable Biomass: Highlights of Downstream Processing and Recovery Techniques
Published in Prasenjit Mondal, Ajay K. Dalai, Sustainable Utilization of Natural Resources, 2017
Sonil Nanda, Ajay K. Dalai, Janusz A. Kozinski
Perstraction is a variation of liquid–liquid extraction in the way that a permeable membrane separates the cell culture from the extracting solvent. This prevents the issues of toxicity and emulsion formation. However, the membranes are usually expensive and often suffer from clogging and fouling due to the bacterial cells. Pervaporation uses the principle of membrane permeation using nonporous membrane followed by evaporation to dehydrate the organic solvent and separate the products. It is less energy intensive and moderately selective compared to liquid–liquid extraction and adsorption. Supercritical fluid, especially SCCO2, has been primordially tested and found to have high butanol selectivity. Although in its infancy, the technology is promising due to its cost-effectiveness, recyclability, and feasibility for larger scale recovery techniques. The advancements in butanol recovery technologies could expedite the development of butanol as a next-generation biofuel for flexible use in the existing vehicular engines and power generation systems.
Production of Butanol from Corn
Published in Shelley Minteer, Alcoholic Fuels, 2016
Thaddeus C. Ezeji, Nasib Qureshi, Patrick Karcher, Hans P. Blaschek
Perstraction is a butanol recovery technique similar to liquid-liquid extraction that seeks to solve some of the problems inherent in liquid-liquid extraction. In a perstraction separation, the fermentation broth and the extractant are separated by a membrane (Qureshi et. al., 1992). The membrane contactor provides a surface area where the two immiscible phases can exchange the butanol. Since there is no direct contact between the two phases, extractant toxicity, phase dispersion, emulsion and rag layer formation are drastically reduced or eliminated. In such a system, butanol should diffuse preferentially across the membrane, while other components such as medium compositions and fermentation intermediates (acetic and butyric acids) should be retained in the aqueous phase. The total mass transport of butanol from the fermentation broth to the organic side depends on the rate of diffusion of butanol across the membrane. The net movement is measured as membrane flux or rate of movement, J = dQb/dt, where J = net flux and dQb/dt = diffusion rate (influx + efflux) of butanol. The membrane does, however, present a physical barrier that can limit the rate of solvent extraction.
Insights into the microbiomes for medium-chain carboxylic acids production from biowastes through chain elongation
Published in Critical Reviews in Environmental Science and Technology, 2022
Xingdong Shi, Lan Wu, Wei Wei, Bing-Jie Ni
Recovering the MCCA products while they are being formed in the fermenter, termed as in-line extraction or in situ product recovery (ISPR), is an ideal approach to relieve the toxicity of the products (Agler et al., 2011). An appropriate ISPR system in the mixed-culture reactor should meet several standards. Firstly, the extractant should be nontoxic to the functional microbes. The direct exposure of microbes to extraction reagents should be avoided if the toxic reagents are necessary for recovering. In addition, the phase separation process (e.g. forcing the electric field) should not affect the CE or other bioprocess. More importantly, the extraction should have a high selectivity to target MCCA products among various organic matters in the fermentation broth. ISPR technologies have been applied to separate short-chain carboxylic acids from fermentation broth, such as adsorption, extraction and electrodialysis (López-Garzón & Straathof, 2014). Currently, researchers have committed to introducing ISPR technology into the recovery of MCCAs (Table S6). The biphasic extraction and the perstraction (or liquid–liquid extraction) are the most common ISPR technologies in MCCAs recovery. The most significant difference between these two methods is that the perstraction system has membrane modules to prevent direct contact between the extractant and the fermentation broth, while the biphasic extraction system does not have this module. The separation principle of biphasic extraction is the same as perstraction system. Therefore, in this review, the perstraction system (also called liquid–liquid extraction system) will be discussed in detail and other possible ISPR technology will also be mentioned to provide references for future research.