Influence of di-rhamnolipids on the enzymatic hydrolysis of steam-pretreated eucalyptus wastes

• Published in: Industrial crops and products 2019-12, Vol.141, p.111835, Article 111835
• Main Authors: Mesquita, Ricardo, Hallwass, Fernando, Santana, Andréa, Baudel, Henrique, Ribeiro, Ester
• Format: Article
• Language: English
• Subjects: Biosurfactants; Di-rhamnolipids; Enzymatic hydrolysis
• ISSN: 0926-6690; 1872-633X
• DOI: 10.1016/j.indcrop.2019.111835

•Di-rhamnolipids can enhance the cellulosic conversion of the eucalyptus wastes.•Di-rhamnolipids can replace Triton X-100 as surfactant for enzymatic hydrolysis.•Use of di-rhamnolipids might eliminate the delignification step of eucalyptus chips.•Di-rhamnolipids might lead to economic benefits in 2 G ethanol production from eucalyptus wastes. In this present work, rhamnolipids produced from Pseudomonas aeruginosa TGC07 were evaluated as biosurfactants for enzymatic hydrolysis of steam pretreated (not delignified) eucalyptus wastes comparatively to the synthetic surfactant Triton X-100. Enzymatic hydrolyses were performed at different substrate loadings (1%, 5% or 10% w/w) using commercial enzymes (Cellic® CTec1) at different dosages (14 or 28 FPU/gcellulose). The di-rhamnolipids were characterized by NMR spectroscopy. Cellulose conversions higher than 60% were achieved after 72 h runtime with the use of di-rhamnolipids at 5% solids, i.e., significantly superior to the conversions obtained from experiments performed without use of any surfactant, and similar to the performance of synthetic Triton X-100 at 5% solids. These results evidence that the use of natural renewable di-rhamnolipids as biosurfactants emerges as an interesting environmentally-friendly alternative to replace synthetic surfactant Triton X-100 as surfactant, aiming to increase production yields of cellulosic sugars by enhancing enzymatic hydrolysis of lignocellulosic biomasses such as steam pretreated eucalyptus wastes.