ABSTRACT

Biobutanol is a potential biofuel produced from various biomass and can serve as a suitable alternative to the nonrenewable fossil-based gasoline fuel. The fermentative microbes used for biobutanol production are solvent-producing Clostridium organisms by Acetone-Butanol-Ethanol (ABE) fermentation. The major challenges of ABE fermentation are butanol toxicity to the host strain, lack of effective fermentation strategies, inefficient butanol separation, and low 0.5–2% w/w yield. Butanol forms an azeotropic mixture with water and requires 79.5 MJ/kg energy for separation using conventional distillation when the energy content of butanol is only 36 MJ/kg; hence the separation by traditional distillation processes is inefficient. Recent developments in membrane technology, coupled with novel extractants and adsorbents, are promising for efficient, energy-effective, and economical bio-butanol separation. Among the techniques, liquid-liquid extraction has shown a high separation efficiency of 75–85% butanol with an energy demand of 25 MJ/kg, whereas adsorption and pervaporation have shown an energy demand of 35–40 MJ/kg. In the present review, a critical analysis of the recent trends, strategies, technical prospects, challenges, and economical evaluation of different methods of biobutanol recovery is presented.

摘要

生物丁醇是一种由各种生物质生产的潜在生物燃料，可以作为不可再生化石汽油燃料的合适替代品。用于生物丁醇生产的发酵微生物是产溶剂梭菌丙酮-丁醇-乙醇（ABE）发酵产生的生物体。ABE 发酵的主要挑战是丁醇对宿主菌株的毒性、缺乏有效的发酵策略、丁醇分离效率低以及 0.5-2% w/w 产量低。丁醇与水形成共沸混合物，当丁醇的能量含量仅为36 MJ/kg时，使用常规精馏分离需要79.5 MJ/kg的能量；因此，传统蒸馏工艺的分离效率低下。膜技术的最新发展，加上新型萃取剂和吸附剂，有望实现高效、节能且经济的生物丁醇分离。其中，液-液萃取技术显示出丁醇分离效率高达 75-85%，能量需求为 25 MJ/kg，而吸附和渗透蒸发的能量需求为 35-40 MJ/kg。在本综述中，对不同生物丁醇回收方法的最新趋势、策略、技术前景、挑战和经济评估进行了批判性分析。