Yeast immobilization with low-cost carrier materials is a suitable strategy to optimize the fermentation of lignocellulosic hydrolysates for the production of second-generation (2G) ethanol. It is defined as the physical confinement of intact cells to a certain region of space (the carrier) with the preservation of their biological activity. This technological approach facilitates promising strategies for second-generation bioethanol production due to the enhancement of the fermentation performance that is expected to be achieved. Using immobilized cells, the resistance to inhibitors contained in the hydrolysates and the co-utilization of sugars are improved, along with facilitating separation operations and the reuse of yeast in new production cycles. Until now, the most common immobilization technology used calcium alginate as a yeast carrier but other supports such as biochar or multispecies biofilm membranes have emerged as interesting alternatives. This review compiles updated information about cell carriers and yeast-cell requirements for immobilization, and the benefits and drawbacks of different immobilization systems for second-generation bioethanol production are investigated and compared.

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用于第二代乙醇生产的酵母固定系统：实际趋势和未来前景

用低成本载体材料固定酵母是优化木质纤维素水解物发酵生产第二代 (2G) 乙醇的合适策略。它被定义为将完整细胞物理限制在某个空间区域（载体），同时保留其生物活性。由于预计将实现的发酵性能的增强，这种技术方法促进了第二代生物乙醇生产的有希望的策略。使用固定化细胞，可以提高对水解产物中所含抑制剂的抵抗力和糖的共同利用，同时促进分离操作和酵母在新生产周期中的再利用。到目前为止，最常见的固定技术使用海藻酸钙作为酵母载体，但其他支持物如生物炭或多物种生物膜已成为有趣的替代品。本综述汇编了有关细胞载体和酵母细胞固定化要求的最新信息，并研究和比较了不同固定化系统在第二代生物乙醇生产中的优缺点。