Akhter Mursheda, Wal Marzan Lolo, Akter Yasmin, Shimizu Kazuyuki
Faculty of Biological Sciences, Department of Genetic Engineering and Biotechnology, University of Chittagong, Chittagong, Bangladesh.
Department of Bioscience & Bioinformatics, Kyushu Institute of Technology, Iizuka, Fukuoka, Japan.
Microbiol Insights. 2020 Apr 28;13:1178636120913280. doi: 10.1177/1178636120913280. eCollection 2020.
In leather industries and tanneries, large amount of wastes has been disposed; which polluting water, soil, and atmosphere and causing serious human health problems. In particular, chemical dehairing process of leather industries produces fair amount of toxic wastes. It is, thus, urgently needed to use alternative processes free from pollution. As more than 90% of keratin is contained in feather, it is desirable to develop bioremediation process using keratinolytic microorganisms. In the present investigation, therefore, we first identified and sp. to be able to produce keratinase. Then, the optimization was performed to maximize the keratinase activity with respect to cultivation temperature, pH, and incubation time. Moreover, the effects of metal ions and various substrates on keratinase activity were also investigated. The result indicates that keratinase activity became maximum at 50°C for both strains, whereas the optimal pH was 10.0 for and 7.0 for sp. The highest keratinase activity of 74.66 ± 1.52 U/mL was attained by , whereas 57.66 ± 2.52 U/mL was attained by sp. Enzymatic dehairing efficiency of leathers was also compared with chemical dehairing (NaS and CaO), where complete dehairing was achieved by treating them with crude keratinase. Partial enzyme purification was performed by acetone precipitation. Batch cultivation of using 1 L fermentor indicates a potential candidate for large-scale keratinase production. Thus, keratinase enzyme by degrading poultry wastes (feather) can be an alternative approach to chemical dehairing in leather industries, thus preventing environmental pollution through bioremediation.
在皮革工业和制革厂中,大量废物被排放;这些废物污染了水、土壤和大气,并引发严重的人类健康问题。特别是,皮革工业的化学脱毛过程会产生大量有毒废物。因此,迫切需要采用无污染的替代工艺。由于羽毛中含有90%以上的角蛋白,因此开发利用角蛋白分解微生物的生物修复工艺是可取的。因此,在本研究中,我们首先鉴定出 和 能够产生角蛋白酶。然后,针对培养温度、pH值和孵育时间进行优化,以最大限度地提高角蛋白酶活性。此外,还研究了金属离子和各种底物对角蛋白酶活性的影响。结果表明,两种菌株的角蛋白酶活性在50°C时均达到最高,而 的最佳pH值为10.0, 的最佳pH值为7.0。 获得的最高角蛋白酶活性为74.66±1.52 U/mL,而 获得的角蛋白酶活性为57.66±2.52 U/mL。还将皮革的酶脱毛效率与化学脱毛(硫化钠和氧化钙)进行了比较,用粗角蛋白酶处理皮革可实现完全脱毛。通过丙酮沉淀进行部分酶纯化。使用1 L发酵罐对 进行分批培养表明其是大规模生产角蛋白酶的潜在候选菌株。因此,通过降解家禽废弃物(羽毛)产生的角蛋白酶可以成为皮革工业化学脱毛的替代方法,从而通过生物修复防止环境污染。