Lipophilic extracts from sugarcane residues: a source of valuable phytochemicals

Sugarcane is an important economic plant in many countries as it is the main feedstock for the production of sugar as well as ethanol, with Brazil leading the world production. The production of sugar from sugarcane generates two main types of wastes, the fibrous residue after extraction of the juice (named bagasse), and the left over harvest residues (straw). Currently, sugarcane residues are mostly burned for the production of heat and electricity at the sugar factory. However, they could also be used as feedstocks for the production of other high-value products in the context of the lignocellulosic biorefinery. Sugarcane bagasse and straw are basically composed of cellulose, hemicelluloses and lignin, but also contain significant amounts of lipids (ca. 1-2% by weight) that can be extracted to obtain high-value products with a wide range of industrial applications in food, cosmetic and pharmaceutical industries. Therefore, in this paper we performed a comprehensive characterization of the lipophilic phytochemicals present in sugarcane bagasse and straw by gas chromatography and mass spectrometry. The analyses revealed that the composition of lipophilic extractives is very different in sugarcane bagasse and straw. The acetone extracts from sugarcane bagasse were dominated by n-aldehydes (ca. 48% of all identified lipids) and n-fatty alcohols (ca. 23%) with lower amounts of n-fatty acids (10%) and steroid ketones (14%), whereas the acetone extracts from sugarcane straw were strongly dominated by n-fatty acids (accounting for ca. 60% of all identified compounds) with significant amounts of steroid compounds, particularly sterols (10%) and steroid ketones (14%). Significant amounts of tocopherols and triterpenols were also found, being particularly abundant among the extractives of sugarcane straw. The information disclosed here opens up new opportunities for the complete industrial utilization of these sugarcane residues from a biorefinery perspective. Due to the large amounts of sugarcane bagasse and straw produced annually, they can be viewed as low-cost and promising sources of highly valuable phytochemicals that can be of use in the cosmetic, food or pharmaceutical industry.This study has been funded by the Spanish project AGL2014-53730-R (co-financed by FEDER funds), the CSIC project 2014-40E-097 and the EU-project INDOX (KBBE-2013-7- 613549). AGL thanks CAPES, and CFL and JLC thank CNPq for financial support.Peer Reviewe