Corn is one of the main crops in China. Large amount of corn straw is potential raw material for the production of biofuels, such as ethanol and butanol. Corn straw is mainly composed of lignin, cellulose and hemicelluloses. Lignin is the most recalcitrant polymers within corn straw, and it is a limiting factor for lignocellulose degradation. Therefore, lignin removal through pretreatment step is critical in the effective lignocellulose utilization. Various pretreatment technologies have been suggested in the last decade, but few are successful in their efficiency.
Prof. Liu Xiaofeng’s group of Chengdu Institute of Biology, Chinese Academy of Sciences has long been committed to the study of pretreatment of corn straw, especially the combination of microbial pretreatment with physical or chemical methods. Recently, they have discovered saccharification of corn straw was enhanced by alkali pretreatment combining crude ligninolytic enzymes. The structure of corn straw before and after pretreatment was further confirmed by SEM images and FTIR spectra.
The authors also explored the monokaryogenesis of dikaryon strains of Trametes hirsuta by protoplasts regeneration for extracellular ligninolytic enzyme production. They determined the best conditions for protoplasts production and regeneration, which was enough for the follow-up experiments.
This work suggested that the NaOH-crude ligninolytic enzyme system is a promising and time-saving technology to pretreat corn straw. In addition, the crude ligninolytic enzyme from protoplasts regenerating monokaryotic strains of Trametes hirsuta showed that it was capable of achieving high sugar yield, thus opening a new source for industrial enzyme production.
The paper was published in the Journal of Chemical Technology and Biotechnology.