Department of Forest Genetics and Plant Physiology, Swedish University of Agricultural Sciences Umea, Sweden.
Front Plant Sci. 2013 May 21;4:118. doi: 10.3389/fpls.2013.00118. eCollection 2013.
Non-cellulosic cell wall polysaccharides constitute approximately one quarter of usable biomass for human exploitation. In contrast to cellulose, these components are usually substituted by O-acetyl groups, which affect their properties and interactions with other polymers, thus affecting their solubility and extractability. However, details of these interactions are still largely obscure. Moreover, polysaccharide hydrolysis to constituent monosaccharides is hampered by the presence of O-acetyl groups, necessitating either enzymatic (esterase) or chemical de-acetylation, increasing the costs and chemical consumption. Reduction of polysaccharide acetyl content in planta is a way to modify lignocellulose toward improved saccharification. In this review we: (1) summarize literature on lignocellulose acetylation in different tree species, (2) present data and current hypotheses concerning the role of O-acetylation in determining woody lignocellulose properties, (3) describe plant proteins involved in lignocellulose O-acetylation, (4) give examples of microbial enzymes capable to de-acetylate lignocellulose, and (5) discuss prospects for exploiting these enzymes in planta to modify xylan acetylation.
非纤维素细胞壁多糖约占人类可利用生物量的四分之一。与纤维素不同，这些成分通常被 O-乙酰基取代，这会影响它们的性质以及与其他聚合物的相互作用，从而影响它们的溶解度和可提取性。然而，这些相互作用的细节在很大程度上仍然不清楚。此外，由于存在 O-乙酰基，多糖水解为组成单糖受到阻碍，需要进行酶（酯酶）或化学脱乙酰化，从而增加成本和化学消耗。在植物体内降低多糖的乙酰基含量是一种对木质纤维素进行修饰以提高糖化的方法。在这篇综述中，我们：（1）总结了不同树种木质纤维素乙酰化的文献；（2）介绍了有关 O-乙酰化在确定木质纤维素性质中的作用的数据和当前假说；（3）描述了参与木质纤维素 O-乙酰化的植物蛋白；（4）给出了能够脱乙酰化木质纤维素的微生物酶的例子；（5）讨论了在植物体内利用这些酶来修饰木聚糖乙酰化的前景。
