posted on 2024-01-30, 10:47authored byKenneth
Sze Kai Teo, Keiko Kondo, Sadat Mohamed Rezk Khattab, Takashi Watanabe, Takashi Nagata, Masato Katahira
Rice straw (RS), an agricultural residue rich in carbohydrates,
has substantial potential for bioethanol production. However, the
presence of lignin impedes access to these carbohydrates, hindering
efficient carbohydrate-to-bioethanol conversion. Here, we expressed
versatile peroxidase (VP), a lignin-degrading enzyme, in Pichia
pastoris and used it to delignify RS at 30 °C using
a membrane bioreactor that continuously discarded the degraded lignin.
Klason lignin analysis revealed that VP-treatment led to 35% delignification
of RS. We then investigated the delignified RS by SEC, FTIR, and SEM.
The results revealed the changes of RS caused by VP-mediated delignification.
Additionally, we compared the saccharification and fermentation yields
between RSs treated with and without VP, VP-RS, and Ctrl-RS, respectively.
This examination unveiled an improvement in glucose and bioethanol
production, VP-RS exhibiting up to 1.5-fold and 1.4-fold production,
respectively. These findings underscore the potential of VP for delignifying
RS and enhancing bioethanol production through an eco-friendly approach.