SAMRC Microbial Water Quality Monitoring Centre, University of Fort Hare, Alice, 5700, South Africa.
Applied and Environmental Microbiology Research Group (AEMREG), Department of Biochemistry and Microbiology, University of Fort Hare, Private Bag X1314 Eastern Cape, Alice, 5700, South Africa.
Biotechnol Lett. 2021 Jul;43(7):1429-1442. doi: 10.1007/s10529-021-03131-z. Epub 2021 Apr 17.
Decaying wood samples were collected, and actinomycetes were isolated and screened for laccase production. The identity of the efficient laccase-producing isolate was confirmed by using a molecular approach. Fermentation conditions for laccase production were optimized, and laccase biochemical properties were studied.
Based on the 16S rRNA gene sequencing and phylogenetic analysis, the isolate coded as HWP was identified as Streptomyces sp. LAO. The time-course study showed that the isolate optimally produced laccase at 84 h with 40.58 ± 2.35 U/mL activity. The optimized physicochemical conditions consisted of pH 5.0, ferulic acid (0.04%; v/v), pine back (0.2 g/L), urea (1.0 g/L), and lactose (1 g/L). Streptomyces sp. LAO laccase was optimally active at pH and temperature of 8.0 and 90 °C, respectively, with remarkable pH and thermal stability. Furthermore, the enzyme had a sufficient tolerance for organic solvents after 16 h of preincubation, with laccase activity > 70%. Additionally, the laccase maintained considerable residual activity after pretreatment with 100 mM of chemical agents, including sodium dodecyl sulphate (69.93 ± 0.89%), ethylenediaminetetraacetic acid (93.1 ± 7.85%), NaN (96.28 ± 3.34%) and urea (106.03 ± 10.72%).
The laccase's pH and thermal stability; and robust catalytic efficiency in the presence of organic solvents suggest its industrial and biotechnological application potentials for the sustainable development of green chemistry.
采集腐朽木材样本，分离并筛选产生漆酶的放线菌。通过分子方法确认高效产漆酶的分离物的身份。优化产漆酶的发酵条件，并研究漆酶的生化特性。
根据 16S rRNA 基因测序和系统发育分析，分离物编码为 HWP，鉴定为链霉菌属 LAO。时程研究表明，该分离物在 84 h 时以 40.58±2.35 U/mL 的活性最佳产漆酶。优化的理化条件为 pH 5.0、阿魏酸（0.04%；v/v）、松块（0.2 g/L）、尿素（1.0 g/L）和乳糖（1 g/L）。链霉菌属 LAO 漆酶在 pH 8.0 和温度 90°C 下最活跃，具有显著的 pH 和热稳定性。此外，该酶在 16 h 的预孵育后对有机溶剂具有足够的耐受性，漆酶活性>70%。此外，该酶在预处理 100 mM 化学试剂后仍保持相当大的残留活性，包括十二烷基硫酸钠（69.93±0.89%）、乙二胺四乙酸（93.1±7.85%）、NaN（96.28±3.34%）和尿素（106.03±10.72%）。
漆酶的 pH 和热稳定性；以及在有机溶剂存在下的强大催化效率表明其具有工业和生物技术应用潜力，可促进绿色化学的可持续发展。
