title: Direct xylan conversion into glycolipid biosurfactants, mannosylerythritol lipids, by Pseudozyma antarctica PYCC 5048(T).
abstract: Mannosylerythritol lipids (MEL) are glycolipid biosurfactants, produced by Pseudozyma spp., with increasing commercial interest. While MEL can be produced from d-glucose and d-xylose, the direct conversion of the respective lignocellulosic polysaccharides, cellulose and xylan, was not reported yet. The ability of Pseudozyma antarctica PYCC 5048(T) and Pseudozyma aphidis PYCC 5535(T) to use cellulose (Avicel(®)) and xylan (beechwood) as carbon and energy source has been assessed along with their capacity of producing cellulolytic and hemicellulolytic enzymes, toward a consolidated bioprocess (CBP) for MEL production. The yeasts assessed were neither able to grow in medium containing Avicel(®) nor produce cellulolytic enzymes under the conditions tested. On contrary, both yeasts were able to efficiently grow in xylan, but MEL production was only detected in P. antarctica PYCC 5048(T) cultures. MEL titers reached 1.3g/l after 10 days in batch cultures with 40g/l xylan, and 2.0g/l in fed-batch cultures with xylan feeding (additional 40g/l) at day 4. High levels of xylanase activities were detected in xylan cultures, reaching 47-62U/ml (31-32U/mg) at 50°C, and still exhibiting more than 10U/ml under physiological temperature (28°C). Total β-xylosidase activities, displayed mainly as wall-bounded and extracellular activity, accounted for 0.154 and 0.176U/ml in P. antarctica PYCC 5048(T) and P. aphidis PYCC 5535(T) cultures, respectively. The present results demonstrate the potential of Pseudozyma spp. for using directly a fraction of lignocellulosic biomass, xylan, and combining in the same bioprocess the production of xylanolytic enzymes with MEL production.
authors.affiliation: Department of Bioengineering and IBB - Institute for Bioengineering and Biosciences, Instituto Superior Técnico, Universidade de Lisboa, Av. Rovisco Pais, 1049-001 Lisboa, Portugal; MIT-Portugal Program, 77 Massachusetts Avenue, E40-221 Cambridge, MA 02139, USA; Laboratório Nacional de Energia e Geologia, I.P., Unidade de Bioenergia, Estrada do Paço do Lumiar 22, 1649-038 Lisboa, Portugal.
authors.forename: Nuno Torres
authors.initials: NT
authors.lastname: Faria
authors.affiliation: Laboratório Nacional de Energia e Geologia, I.P., Unidade de Bioenergia, Estrada do Paço do Lumiar 22, 1649-038 Lisboa, Portugal.
authors.forename: Susana
authors.initials: S
authors.lastname: Marques
authors.affiliation: Laboratório Nacional de Energia e Geologia, I.P., Unidade de Bioenergia, Estrada do Paço do Lumiar 22, 1649-038 Lisboa, Portugal. Electronic address: cesar.fonseca@lneg.pt.
authors.forename: César
authors.initials: C
authors.lastname: Fonseca
authors.affiliation: Department of Bioengineering and IBB - Institute for Bioengineering and Biosciences, Instituto Superior Técnico, Universidade de Lisboa, Av. Rovisco Pais, 1049-001 Lisboa, Portugal. Electronic address: frederico.ferreira@tecnico.ulisboa.pt.
authors.forename: Frederico Castelo
authors.initials: FC
authors.lastname: Ferreira
mesh_terms: D061249:Batch Cell Culture Techniques; D044602:Cellulases / Q000378:metabolism; D002482:Cellulose / Q000378:metabolism; D043364:Endo-1,4-beta Xylanases / Q000378:metabolism; D005656:Fungal Proteins / Q000378:metabolism; D006017:Glycolipids / Q000096:biosynthesis*; D007218:Industrial Microbiology; D007700:Kinetics; D013501:Surface-Active Agents / Q000378:metabolism*; D014587:Ustilaginales / Q000201:enzymology / Q000378:metabolism*; D014990:Xylans / Q000378:metabolism*
chemical_list: D005656:Fungal Proteins; D006017:Glycolipids; D013501:Surface-Active Agents; D014990:Xylans; C439671:mannosylerythritol lipid; D002482:Cellulose; D044602:Cellulases; D043364:Endo-1,4-beta Xylanases
keywords: Cellulases-free xylanases; Consolidated bioprocessing; Mannosylerythritol lipids (MEL); Pseudozyma spp.; Xylan