Objectives

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.

Results

Based on the 16S rRNA gene sequencing and phylogenetic analysis, the isolate coded as HWP₃ 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%), NaN₃ (96.28 ± 3.34%) and urea (106.03 ± 10.72%).

Conclusion

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.

中文翻译：

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由 Streptomyces sp. 产生的耐热和耐溶剂漆酶的表征。老挝

目标

收集腐烂的木材样品，分离放线菌并筛选生产漆酶。通过使用分子方法确认了高效产漆酶分离株的身份。优化了生产漆酶的发酵条件，研究了漆酶生化特性。

结果

基于16S rRNA基因测序和系统发育分析，编码为HWP ₃的分离株被鉴定为链霉菌属。老挝。时间进程研究表明，该分离株在 84 小时时最佳地产生漆酶，活性为 40.58 ± 2.35 U/mL。优化的理化条件包括 pH 5.0、阿魏酸 (0.04%; v/v)、松背 (0.2 g/L)、尿素 (1.0 g/L) 和乳糖 (1 g/L)。链霉菌sp. LAO 漆酶在 pH 值和温度分别为 8.0 和 90 °C 时具有最佳活性，具有显着的 pH 值和热稳定性。此外，该酶在预孵育 16 小时后对有机溶剂具有足够的耐受性，漆酶活性 > 70%。此外，漆酶在用 100 mM 化学试剂预处理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 ₃ (96.28 ± 3.34%) 和尿素 (106.03) 10.72%）。

结论

漆酶的pH值和热稳定性；在有机溶剂存在下的强大催化效率表明其在工业和生物技术方面的应用潜力对于绿色化学的可持续发展。