Akram Fatima, Aqeel Amna, Shoaib Minahil, Haq Ikram Ul, Shah Fatima Iftikhar
Institute of Industrial Biotechnology, Government College University, Lahore, 54000, Pakistan.
Pakistan Academy of Science, Islamabad, Pakistan.
Environ Sci Pollut Res Int. 2022 Dec;29(58):86913-86932. doi: 10.1007/s11356-022-23638-w. Epub 2022 Oct 22.
Since the dawn of century, tons of keratin bio-waste is generated by the poultry industry annually, and they end up causing environmental havoc. Keratins are highly flexible fibrous proteins which exist in α- and β- forms and provide mechanical strength and stability to structural appendages. The finding of broad-spectrum protease, keratinase, from thermophilic bacteria and fungi, has provided an eco-friendly solution to hydrolyze the peptide bonds in highly recalcitrant keratinous substances such as nails, feathers, claws, and horns into valuable amino acids. Microorganisms produce these proteolytic enzymes by techniques of solid-state and submerged fermentation. However, solid-state fermentation is considered as a yielding approach for the production of thermostable keratinases. This review prioritized the molecular and biochemical properties of microbial keratinases, and the role of keratinases in bringing prodigious impact for the sustainable progress of the economy. It also emphasizes on the current development in keratinase production with the focus to improve the biochemical properties related to enzyme's catalytic activity and stability, and production of mutant and cloned microbial strains to improve the yield of keratinases. Recently, multitude molecular approaches have been employed to enhance enzyme's productivity, activity, and thermostability which makes them suitable for pharmaceutical industry and for the production of animal feed, organic fertilizers, biogas, clearing of animal hides, and detergent formulation. Hence, it can be surmised that microbial keratinolytic enzymes are the conceivable candidates for numerous commercial and industrial applications.
自本世纪初以来，家禽业每年都会产生数吨角蛋白生物废料，这些废料最终对环境造成严重破坏。角蛋白是高度灵活的纤维蛋白，以α-和β-形式存在，为结构附属物提供机械强度和稳定性。从嗜热细菌和真菌中发现的广谱蛋白酶——角蛋白酶，为将指甲、羽毛、爪子和角等高度难降解的角蛋白物质中的肽键水解为有价值的氨基酸提供了一种环保解决方案。微生物通过固态发酵和深层发酵技术产生这些蛋白水解酶。然而，固态发酵被认为是生产耐热角蛋白酶的一种有效方法。本综述重点介绍了微生物角蛋白酶的分子和生化特性，以及角蛋白酶在为经济的可持续发展带来巨大影响方面的作用。它还强调了角蛋白酶生产的当前进展，重点是改善与酶的催化活性和稳定性相关的生化特性，以及生产突变体和克隆微生物菌株以提高角蛋白酶的产量。最近，人们采用了多种分子方法来提高酶的生产力、活性和热稳定性，这使得它们适用于制药行业以及动物饲料、有机肥料、沼气的生产、动物皮革的清理和洗涤剂配方。因此，可以推测微生物角蛋白水解酶是众多商业和工业应用中值得考虑的候选者。
