Towards enhanced n-butanol production from sugarcane bagasse hemicellulosic hydrolysate: Strain screening, and the effects of sugar concentration and butanol tolerance

Author(s)

Zetty-Arenas, Ana Maria ^{[1, 2, 3]} ; Alves, Rafael Ferraz ^[2] ; Freixo Portela, Carla Andreia ^[2] ; Mariano, Adriano Pinto ^[1] ; Basso, Thiago Olitta ^[4] ; Tovar, Laura Plazas ^[5] ; Maciel Filho, Rubens ^[1] ; Freitas, Sindelia ^{[1, 2]}

Affiliation

^[1] Univ Estadual Campinas, UNICAMP, Sch Chem Engn, Campinas, SP - Brazil

^[2] Brazilian Ctr Res Energy & Mat CTBE CNPEM, Brazilian Bioethanol Sci & Technol Lab, Campinas, SP - Brazil

^[3] Delft Univ Technol TU Delft, Dept Biotechnol, Delft - Netherlands

^[4] Univ Sao Paulo, Dept Chem Engn, Sao Paulo, SP - Brazil

^[5] Fed Univ Sao Paulo UNIFESP, Dept Chem Engn, Diadema, SP - Brazil

• Document type: Journal article
• Source: BIOMASS & BIOENERGY; v. 126, p. 190-198, JUL 2019.
• Web of Science Citations: 1

Abstract

Robust strains are essential towards success of n-butanol production from lignocellulosic feedstock. To find a suitable strain to convert a non-detoxified hemicellulosic hydrolysate of sugarcane bagasse, we first assessed the performance of four wild-type butanol-producing Clostridium strains (C. acetobutylicum DSM 6228, C. beijerinckii DSM 6422, C. saccharobutylicum DSM 13864, and C. saccharoperbutylacetonicum DSM 14923) in batch fermentations containing either xylose or glucose at 30 g L-1 as sole carbon sources. C. saccharoperbutylacetonicum was selected after achieving butanol yields as high as 0.31 g g(-1) on glucose and 0.25 g g(-1) on xylose. In a 48-h fermentation containing a mixture of sugars (93% xylose and 7% glucose) that mimicked the hydrolysate, C. saccharoperbutylacetonicum delivered the highest butanol concentration (14.5 g L-1) when the initial sugar concentration was 50 g L-1. Moreover, the selected strain achieved the highest butanol yield (0.29 g g(-1)) on xylose-rich media reported so far. Meanwhile, C. saccharoperbutylacetonicum produced 5.8 g butanol L-1 (0.22 g g(-1) butanol yield) when fermenting a non-detoxified sugarcane bagasse hemicellulosic hydrolysate enriched with xylose (30 g total sugars L-1). Although sugars were not exhausted (4.7 g residual sugars L-1) even after 72 h because of the presence of lignocellulose-derived microbial inhibitors, these results show that C. saccharoperbutylacetonicum is a robust wild-type strain. This microorganism with high butanol tolerance and yield on xylose can, therefore, serve as the basis for the development of improved biocatalysts for production of butanol from non-detoxified sugarcane bagasse hemicellulosic hydrolysate. (AU)

• FAPESP's process: 15/20630-4 - Biorefinery development integrated to a bioethanol sugar cane plant with zero CO2 emission: routes to convert renewable resources to bio-products and bio-electricity
• Grantee: Rubens Maciel Filho
• Support Opportunities: Research Projects - Thematic Grants