Cellulose Enzymatic Saccharification Intensified by Nonionic Surfactants

Abstract

Enzymatic saccharification of cellulose is one of the bottlenecks of second-generation bioethanol production and other bioprocesses aimed at the use of lignocellulosic residues. Hence, it is crucial to find conditions and additives that can improve this process. In this work, the use of different nonionic surfactants was studied. The results demonstrate that all tested additives increase the initial rate of filter paper saccharification, with PEG 600 more than doubling the initial rate for two cellulose enzymatic cocktails. The highest effects were found with surfactants of linear structure, which likely better separate the filter paper cellulose fibers, allowing enzyme access. The effect of surfactants was larger for experiments without agitation. However, orbital agitation improved both the initial rate and yields. The effect of the gas-liquid interfacial area was negligible. Despite the beneficial trends found for the filter paper, no significant improvements were evidenced while adding surfactants to the saccharification of acid-oxidative pretreated biomass. Similarly, carboxymethyl cellulose saccharification was only marginally enhanced. Hence, the substrate structure and delignification method have a strong effect on the influence of surfactant addition and should be considered for deciding the saccharification media formulation.