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Design of selective production of sophorolipids by Rhodotorula bogoriensis through nutritional requirements
Author(s) -
Ribeiro Isabel A.,
Bronze Maria R.,
Castro Matilde F.,
Ribeiro Maria H.L.
Publication year - 2012
Publication title -
journal of molecular recognition
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.401
H-Index - 79
eISSN - 1099-1352
pISSN - 0952-3499
DOI - 10.1002/jmr.2188
Subject(s) - chemistry , chromatography , electrospray ionization , fermentation , hydrophilic interaction chromatography , high performance liquid chromatography , laboratory flask , mass spectrometry , organic chemistry
Rhodotorula bogoriensis is known as the producer of longer chain acidic sophorolipids (SLs) with a unique hydroxylation position where the sophorose unit is linked to the 13‐hydroxydocosanoic acid. The influence of initial inoculum concentration, hydrophilic and hydrophobic carbon, and nitrogen sources on R. bogoriensis growth and SL production was evaluated to obtain a selective SL production. Experiments took place in microtiter plates, used as minireactors, after the verification of its suitability compared with shake flasks. The common structure of SLs is the 13‐[2′‐ O ‐β‐ d ‐glucopyranosyl‐ β ‐ d ‐glucopyranosyloxy]‐docosanoic acid SL. The analysis of the fermentation media using high‐performance liquid chromatography with evaporative light scattering detector showed the production of four main SLs, respectively, in the following forms: (i) deacetylated (peak A) (C22:0 SL), (ii) 6″monoacetylated (peak B) (C22:0‐6″Ac SL), (iii) 6′monoacetylated (peak C) (C22:0‐6′Ac SL), and (iv) 6′,6″ diacetylated (peak D) (C22:0‐6′,6″Ac SL). The identification of compounds in SL mixtures was performed by liquid chromatography with electrospray ionization mass spectrometry analysis, and no differences were observed. Besides the four compounds detected using high‐performance liquid chromatography with evaporative light scattering detector chromatograms, three other SLs was identified, corresponding to mono‐ and diacetylated C24:0 hydroxy fatty acid SLs. To our knowledge, this work presents for the first time the production and identification of C24:0 SLs. A longer hydrophobic tail on SLs had an important role in the improvement of surface active properties. The selection of a specific time for fermentation end and the use of different carbon (e.g. glucose, fructose, mannose, lactose, galactose, xylose) and nitrogen (e.g. peptone, (NH 4 ) 2 SO 4 and NaNO 3 ) sources led to a selective production of de‐, mono‐, and diacetylated SLs by R. bogoriensis . Copyright © 2012 John Wiley & Sons, Ltd.