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Microbial degradation of ether bonds between carbohydrates and residual lignin from kraft pulp

硫酸盐纸浆中碳水化合物和残留木质素之间醚键的微生物降解

基本信息

批准号：
05660189
负责人：
WATANABE Takashi
金额：
$ 1.34万
依托单位：
KYOTO UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (C)
财政年份：
1993
资助国家：
日本
起止时间：
1993 至 1994
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-05660189/
关键词：
Kraft Pulp Biobleaching LCC White-rot fungi Lignin

项目摘要

A water-soluble xylanase-resitant chromophoric xylan fraction (LF-D) was separated from a hard wood unbleached kraft pulp (UKP) by a cellulase/xylanase bioreactor and silica gel column chromatography. Chemical and spectroscopic analyzes revealed that LF-D contained a large amount of unremovable inorganic atoms including Si, Na and S,together with non-branched beta-1,4-linked xylan chain. In a nitrobenzen oxidation of LF-D,existence of a large amount of qunoid structure was suggested. In adittion, it was found that lignin in LF-D had been demethylated during the course of kraft pulping. On the other hand, a higher molecular weight residual fraction (HF-P) was found to contain much diphenylmethane (DPM) structure. LF-D was more effectively decolorized by bacterial microflora from soil rather than selected white rot fung. However, C.versocolor was found to decolorize both the chromophric xylan fraction and intact UKP itself among the white-rot fungi tested. In both cases, activities of lignin peroxidase, Mn-peroxidase, laccase and xylanase were not detected during the hole time of cultivation.Although a purified LiP (H8) from P.chrysosporium wa oxidized a p-ethylated beta-O-4LCC model, carbohydrate moiety was not detected in the reaction mixture. Therefore, screening of microorganisms which quantitatively cleave p-etherified benzyl ether bonds was carried out using a fluorescence-sensitive benzyl ether model compound. As a result, several bacterial single colonies which emit fluorescence were isolated. Further study on the characterization of these microorgansims would lead to an environmentally safe biobleaching system of pulps.

采用纤维素酶/木聚糖酶生物反应器和硅胶柱层析技术，从阔叶木未漂硫酸盐浆（UKP）中分离得到一种水溶性木聚糖酶抗性发色木聚糖组分（LF-D）。化学和光谱分析表明，LF-D含有大量不可去除的无机原子，包括Si，Na和S，以及非支化的β-1，4-连接的木聚糖链。在硝基苯氧化LF-D的反应中，存在大量的类喹啉结构。另外，在硫酸盐法制浆过程中，发现LF-D中的木质素发生了脱甲基反应。另一方面，发现较高分子量的残余馏分（HF-P）含有较多的二苯基甲烷（CH_4）结构。从土壤中提取的细菌对LF-D的脱色效果优于筛选出的白色腐菌。然而，在所测试的白腐真菌中，发现C.versocolor使发色木聚糖级分和完整的UKP本身脱色。在这两种情况下，在培养的孔时间内没有检测到木质素过氧化物酶、锰过氧化物酶、漆酶和木聚糖酶的活性。虽然从P.chrysosporium纯化的LiP（H8）氧化对乙基化的β-O-4LCC模型，但在反应混合物中没有检测到碳水化合物部分。因此，使用荧光敏感性苄基醚模型化合物进行定量断裂β-醚化苄基醚键的微生物的筛选。结果，分离出几个发射荧光的细菌单菌落。进一步研究这些微生物的特性将导致一个环境安全的纸浆生物漂白系统。