Moreira MT, Feijoo G, Mester T, Mayorga P, Sierra-Alvarez R, Field JA
Division of Wood Science, Department of Forestry, Wageningen Agricultural University, Wageningen, The Netherlands.
Appl Environ Microbiol. 1998 Jul 1;64(7):2409-17. doi: 10.1128/AEM.64.7.2409-2417.1998.
Bjerkandera sp. strain BOS55 is a white rot fungus that can bleach EDTA-extracted eucalyptus oxygen-delignified kraft pulp (OKP) without any requirement for manganese. Under manganese-free conditions, additions of simple physiological organic acids (e.g., glycolate, glyoxylate, oxalate, and others) at 1 to 5 mM stimulated brightness gains and pulp delignification two- to threefold compared to results for control cultures not receiving acids. The role of the organic acids in improving the manganese-independent biobleaching was shown not to be due to pH-buffering effects. Instead, the stimulation was attributed to enhanced production of manganese peroxidase (MnP) and lignin peroxidase (LiP) as well as increased physiological concentrations of veratryl alcohol and oxalate. These factors contributed to greatly improved production of superoxide anion radicals, which may have accounted for the more extensive biobleaching. Optimum biobleaching corresponded most to the production of MnP. These results suggest that MnP from Bjerkandera is purposefully produced in the absence of manganese and can possibly function independently of manganese in OKP delignification. LiP probably also contributed to OKP delignification when it was present.
Bjerkandera sp.菌株BOS55是一种白腐真菌，它能够在无需任何锰的情况下对经乙二胺四乙酸（EDTA）提取的桉木氧脱木素硫酸盐浆（OKP）进行漂白。在无锰条件下，添加1至5 mM的简单生理性有机酸（如乙醇酸、乙醛酸、草酸等），与未添加酸的对照培养物相比，可使白度增加和纸浆脱木素程度提高两到三倍。结果表明，有机酸在改善不依赖锰的生物漂白过程中的作用并非源于pH缓冲效应。相反，这种促进作用归因于锰过氧化物酶（MnP）和木质素过氧化物酶（LiP）产量的提高，以及藜芦醇和草酸盐生理浓度的增加。这些因素促使超氧阴离子自由基的产量大幅提高，这可能是更广泛生物漂白的原因。最佳生物漂白效果与MnP的产量最为相关。这些结果表明，Bjerkandera的MnP在无锰情况下有目的地产生，并且在OKP脱木素过程中可能独立于锰发挥作用。当LiP存在时，它可能也有助于OKP的脱木素。
