Development of new strategies to add-value to agro-industrial by-products are of environmental and economical importance. Innovative and low-cost sources of protein and bioactive peptides have been explored worldwide. Spent brewer’s yeast (SBY) is the second most relevant by-product from the brewing industry, and despite its nutritional (about 50% protein, dry weight) and technological potential, it is still underused or needs to be disposed of. SBY cells need to be disrupted to release intracellular and cell wall proteins. This procedure has been performed using autolysis, glass bead milling, enzymatic hydrolysis and ultrasound processing. Enzymatic treatment is usually performed without prior purification and is a challenging process, which involves multiple factors, but has been successfully used as a strategy to add value to agro-industrial by-products. Scope and approach: in this review, we particularly focused on enzymatic hydrolysis as a strategy to promote SBY valorisation, illustrating the state-of-the-art processes used to produce protein extracts from this material as well as exploring fundamental concepts related to the particularities of yeast cell disruption and protein hydrolysis. Furthermore, innovative applications of value-added yeast by-products in food, biotechnological and pharmaceutical industries are presented and discussed. Key findings and conclusions: the discovery of valuable compounds found in spent yeasts as well as the development of new processing methodologies have been widening the possibilities of reuse and transformation of SBY as an ingredient and innovative matrix. Once released, yeast proteins and peptides may be applied as an innovative non-animal protein source or a functional and bioactive ingredient.

中文翻译：

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废啤酒酵母作为高附加值分子的来源：对其特性、加工和潜在应用的系统评价

开发新战略以增加农工业副产品的价值具有环境和经济重要性。全世界都在探索蛋白质和生物活性肽的创新和低成本来源。废啤酒酵母 (SBY) 是啤酒行业第二大相关副产品，尽管它具有营养（约 50% 的蛋白质，干重）和技术潜力，但仍未得到充分利用或需要处理。SBY 细胞需要被破坏以释放细胞内和细胞壁蛋白。该过程已使用自溶、玻璃珠研磨、酶水解和超声处理进行。酶处理通常无需事先纯化即可进行，是一个具有挑战性的过程，涉及多种因素，但已成功用作增加农工业副产品价值的战略。范围和方法：在本次审查中，我们特别关注酶水解作为促进 SBY 价值化的策略，说明了用于从这种材料中生产蛋白质提取物的最先进工艺，以及探索与特殊性相关的基本概念酵母细胞破碎和蛋白质水解。此外，还介绍和讨论了高附加值酵母副产品在食品、生物技术和制药行业的创新应用。主要发现和结论：在废酵母中发现有价值的化合物以及新加工方法的开发扩大了 SBY 作为成分和创新基质的再利用和转化的可能性。