Enzymatic modification of lignin and its application in phenol-formaldehyde based polymers

该提案解决了使用酶促方法对木质素进行改性的问题，并将补充加拿大其他地方正在进行的木质素化学改性研究计划。用酶对天然聚合物（如木质素）进行改性是一种环境友好的替代方法，可以替代更苛刻的化学方法。此外，酶的特异性被利用，因为它们靶向聚合物表面上的特定官能团而不破坏聚合物本身。从北方森林收集的木材腐烂真菌的密集筛选计划，并安置在湖首大学的真菌标本馆将进行搜索参与木质素改性（氧化和水解反应）的酶。特别感兴趣的是从硫酸盐和蒸汽爆破衍生的木质素中特异性地切割甲基（脱甲基化）和甲氧基（脱乙氧基化）的酶。据我们所知，这种活性类型的酶尚未在科学文献中描述，尽管有证据表明甲醇（甲基去除的结果）是由木质素分解真菌从木质素中释放出来的。由于木质素是一种高度甲基化的天然聚合物，因此特定的酶可能与木质素的去甲基化有关。这些将通过筛选来寻找。真菌（和酶）：与木质素脱甲基化相关的活性可以通过测量释放的甲醇来测定。本研究的目的是发现和分离能够通过脱甲基反应修饰木质素的微生物酶，并阐明其作用机理。木质素脱甲基化酶将大规模生产，并且粗产物以及纯化形式的物理化学性质被表征，因为该信息在木质素的酶促改性的下游研究中至关重要。所述酶将用于木质素的脱甲基化和优化的条件，并且评估脱甲基化产物在甲醛聚合物应用中作为苯酚替代物的反应性。的总体结果

This proposal addresses the modification of lignin using an enzymatic approach, and will complement research programs on chemical modification of lignin in progress elsewhere in Canada. The modification of natural polymers such as lignin with enzymes is an environmentally-friendly alternative to the harsher chemical method. Moreover, the specificity of enzymes is exploited as they target specific functional groups on polymer surfaces without destroying the polymer itself. An intensive screening program of wood-decay fungi collected from the Boreal Forest and housed in the Mycological Herbarium at Lakehead University will be conducted to search for enzymes involved in lignin modification (oxidation and hydrolysis reactions).-of particular interest, are enzymes that specifically cleave-off methyl (demethylation) and methoxyl groups (dernethoxylation) from Kraft and steam explosion-derived lignins. To our knowledge, enzymes of this activity type have not yet been described in the scientific literature, although there is evidence that methanol (result of methyl removal) is liberated from lignin by ligninolytic fungi. As lignin is a highly methylated natural polymer, specific enzymes are likely associated with demethylation of lignin. These will be sought through screening. Fungi (and enzyme: activity associated with demethylation of lignin can be assayed by measuring methanol released. The objective of this proposal is to discover and isolate microbial enzymes that can modify lignin through demethylation reactions, and to elucidate this mechanism. The lignin demethylating enzyme(s) will be produced on a large scale, and the physicochemical properties of the crude, as well as in the purified form, characterised as this information is vitally important in downstream studies on the enzymatic modification of lignin. The enzyme(s) will be employed in the demethylation of lignin and conditions optimised, and the demethylated product assessed for reactivity as a substitute for phenol in formaldehyde polymer applications. The overall outcome of