Aureobasidium pullulans is a common, ubiquitous fungus, which is used industrially to produce the polysaccharide pullulan. We have previously shown that A. pullulans produces various heavier-than-water oils, first named here as liamocins, that accumulate in fermentations. Here we report the structural characterization of four liamocins, A1, A2, B1, and B2, produced by A. pullulans strain NRRL 50380 using a combination of MALDI-TOF/MS, quadrupole-TOF/MS, isotopic labeling, NMR, GC/MS, and classical carbohydrate analysis. The data showed that the liamocins are composed of a single mannitol headgroup partially O-acylated with three (for liamocin A1 and A2) or four (for liamocin B1 and B2) 3,5-dihydroxydecanoic ester groups. Liamocins A1 and B1 are non-acetylated, whereas A2 and B2 each contain a single 3'-O-acetyl group. Each of these compounds is characterized by pseudomolecular [M+Na](+) ions in the MALDI-TOF/MS spectra at m/z 763.22, 949.35, 805.22, and 991.37, respectively. The 186Da mass difference between A-type and B-type liamocins corresponds to one O-linked 3,5-dihydroxydecanoate group. HMBC NMR showed that one 3,5-dihydroxydecanoate carbonyl group is ester linked to a primary hydroxyl on the mannitol. Other long range (13)C-(1)H couplings across 1,5-ester bridges showed that the 3,5-dihydroxydecanoate groups form 1-5-linked polyester chains, similar in structure to the antibiotic substance exophilin A. Moreover, the MS analysis identified several non-conjugated poly-3,5-dihydroxydecanoate esters as minor components that are tentatively assigned as exophilins A1, A2, B1, and B2. The liamocins, and three of the exophilins, are new, previously unreported structures.

biosurfactants, Aureobasidium pullulans, liamocins, polyol oils, MALDI-TOF/MS, exophilins

13C NMR data:
Linkage	Residue	C1	C2	C3	C4	C5	C6	C7	C8	C9	C10	C11	C12	C13	C14	C15	C16	C17	C18	C19	C20	C21	C22	C23	C24	C25	C26	C27	C28	C29	C30	C31	C32	C33	C34	C35	C36	C37	C38	C39
1	xDMan-ol	63.7	68.8	69.7	69.7	71.5	66.5
	Subst	172.9	43.4	66.7	41.9	43.7	73.4	35.0	38.4	25.6	25.8	32.4	23.4	14.4	172.9	43.4	66.7	41.9	43.7	73.4	35.0	38.4	25.6	25.8	32.4	23.4	14.4	172.9	43.4	66.7	41.9	43.7	73.4	35.0	38.4	25.6	25.8	32.4	23.4	14.4


1H NMR data:
Linkage	Residue	H1	H2	H3	H4	H5	H6	H7	H8	H9	H10	H11	H12	H13	H14	H15	H16	H17	H18	H19	H20	H21	H22	H23	H24	H25	H26	H27	H28	H29	H30	H31	H32	H33	H34	H35	H36	H37	H38	H39	H40	H41	H42	H43	H44	H45
1	xDMan-ol	3.65-3.80	3.89	3.8	3.8	3.71	4.20-4.38
	Subst	-	2.38-2.48	4.05	1.68-1.79	1.54-1.60	5.04	1.56	1.40	1.25	1.25	1.27	1.26	0.85	-	2.38	2.48	4.05	1.68	1.79	1.54	1.60	5.04	1.56	1.40	1.25	1.25	1.27	1.26	0.85	-	2.38	2.48	4.05	1.68	1.79	1.54	1.60	5.04	1.56	1.40	1.25	1.25	1.27	1.26	0.85


1H/13C HSQC data:
Linkage	Residue	C1/H1	C2/H2	C3/H3	C4/H4	C5/H5	C6/H6	C7/H7	C8/H8	C9/H9	C10/H10	C11/H11	C12/H12	C13/H13	C14/H14	C15/H15	C16/H16	C17/H17	C18/H18	C19/H19	C20/H20	C21/H21	C22/H22	C23/H23	C24/H24	C25/H25	C26/H26	C27/H27	C28/H28	C29/H29	C30/H30	C31/H31	C32/H32	C33/H33	C34/H34	C35/H35	C36/H36	C37/H37	C38/H38	C39/H39	C40/H40	C41/H41	C42/H42	C43/H43	C44/H44	C45/H45
1	xDMan-ol	63.7/3.65-3.80	68.8/3.89	69.7/3.8	69.7/3.8	71.5/3.71	66.5/4.20-4.38
	Subst	NMR TSV error 2: unequal length of 13C and 1H datasets

There is only one chemically distinct structure:

SVGMWSMILES3D molIonize

 

CCCCCC(O)CC(O)CC(=O)OC(CCCCC)CC(O)CC(=O)OC(CCCCC)CC(O)CC(=O)OC[C@@H](O)[C@@H](O)[C@H](O)[C@H](O)CO

740.925 g/mol (C₃₆H₆₈O₁₅)

Aureobasidium pullulans is a common, ubiquitous fungus, which is used industrially to produce the polysaccharide pullulan. We have previously shown that A. pullulans produces various heavier-than-water oils, first named here as liamocins, that accumulate in fermentations. Here we report the structural characterization of four liamocins, A1, A2, B1, and B2, produced by A. pullulans strain NRRL 50380 using a combination of MALDI-TOF/MS, quadrupole-TOF/MS, isotopic labeling, NMR, GC/MS, and classical carbohydrate analysis. The data showed that the liamocins are composed of a single mannitol headgroup partially O-acylated with three (for liamocin A1 and A2) or four (for liamocin B1 and B2) 3,5-dihydroxydecanoic ester groups. Liamocins A1 and B1 are non-acetylated, whereas A2 and B2 each contain a single 3'-O-acetyl group. Each of these compounds is characterized by pseudomolecular [M+Na](+) ions in the MALDI-TOF/MS spectra at m/z 763.22, 949.35, 805.22, and 991.37, respectively. The 186Da mass difference between A-type and B-type liamocins corresponds to one O-linked 3,5-dihydroxydecanoate group. HMBC NMR showed that one 3,5-dihydroxydecanoate carbonyl group is ester linked to a primary hydroxyl on the mannitol. Other long range (13)C-(1)H couplings across 1,5-ester bridges showed that the 3,5-dihydroxydecanoate groups form 1-5-linked polyester chains, similar in structure to the antibiotic substance exophilin A. Moreover, the MS analysis identified several non-conjugated poly-3,5-dihydroxydecanoate esters as minor components that are tentatively assigned as exophilins A1, A2, B1, and B2. The liamocins, and three of the exophilins, are new, previously unreported structures.

biosurfactants, Aureobasidium pullulans, liamocins, polyol oils, MALDI-TOF/MS, exophilins

13C NMR data:
Linkage	Residue	C1	C2	C3	C4	C5	C6	C7	C8	C9	C10	C11	C12	C13	C14	C15	C16	C17	C18	C19	C20	C21	C22	C23	C24	C25	C26	C27	C28	C29	C30	C31	C32	C33	C34	C35	C36	C37	C38	C39
1,3	xDMan-ol	63.7	68.8	69.7	69.7	71.5	66.5
1	Subst	172.9	43.4	66.7	41.9	43.7	73.4	35.0	38.4	25.6	25.8	32.4	23.4	14.4	172.9	43.4	66.7	41.9	43.7	73.4	35.0	38.4	25.6	25.8	32.4	23.4	14.4	172.9	43.4	66.7	41.9	43.7	73.4	35.0	38.4	25.6	25.8	32.4	23.4	14.4
	Ac	171.3	20.0


1H NMR data:
Linkage	Residue	H1	H2	H3	H4	H5	H6	H7	H8	H9	H10	H11	H12	H13	H14	H15	H16	H17	H18	H19	H20	H21	H22	H23	H24	H25	H26	H27	H28	H29	H30	H31	H32	H33	H34	H35	H36	H37	H38	H39	H40	H41	H42	H43	H44	H45
1,3	xDMan-ol	3.65-3.80	3.89	3.80	3.80	3.71	4.20-4.38
1	Subst	-	2.38-2.48	4.05	1.68-1.79	1.54-1.60	5.04	1.56	1.40	1.25	1.25	1.27	1.26	0.85	-	2.38	2.48	4.05	1.68	1.79	1.54	1.60	5.04	1.56	1.40	1.25	1.25	1.27	1.26	0.85	-	2.38	2.48	4.05	1.68	1.79	1.54	1.60	5.04	1.56	1.40	1.25	1.25	1.27	1.26	0.85
	Ac	-	2.00


1H/13C HSQC data:
Linkage	Residue	C1/H1	C2/H2	C3/H3	C4/H4	C5/H5	C6/H6	C7/H7	C8/H8	C9/H9	C10/H10	C11/H11	C12/H12	C13/H13	C14/H14	C15/H15	C16/H16	C17/H17	C18/H18	C19/H19	C20/H20	C21/H21	C22/H22	C23/H23	C24/H24	C25/H25	C26/H26	C27/H27	C28/H28	C29/H29	C30/H30	C31/H31	C32/H32	C33/H33	C34/H34	C35/H35	C36/H36	C37/H37	C38/H38	C39/H39	C40/H40	C41/H41	C42/H42	C43/H43	C44/H44	C45/H45
1,3	xDMan-ol	63.7/3.65-3.80	68.8/3.89	69.7/3.80	69.7/3.80	71.5/3.71	66.5/4.20-4.38
1	Subst	NMR TSV error 2: unequal length of 13C and 1H datasets
	Ac		20.0/2.00

There is only one chemically distinct structure:

SVGMWSMILES3D molIonize

 

CCCCCC(O)CC(O)CC(=O)OC(CCCCC)CC(O)CC(=O)OC(CCCCC)CC(CC(=O)OC(C)=O)OC[C@@H](O)[C@@H](O)[C@H](O)[C@H](O)CO

782.962 g/mol (C₃₈H₇₀O₁₆)

Aureobasidium pullulans is a common, ubiquitous fungus, which is used industrially to produce the polysaccharide pullulan. We have previously shown that A. pullulans produces various heavier-than-water oils, first named here as liamocins, that accumulate in fermentations. Here we report the structural characterization of four liamocins, A1, A2, B1, and B2, produced by A. pullulans strain NRRL 50380 using a combination of MALDI-TOF/MS, quadrupole-TOF/MS, isotopic labeling, NMR, GC/MS, and classical carbohydrate analysis. The data showed that the liamocins are composed of a single mannitol headgroup partially O-acylated with three (for liamocin A1 and A2) or four (for liamocin B1 and B2) 3,5-dihydroxydecanoic ester groups. Liamocins A1 and B1 are non-acetylated, whereas A2 and B2 each contain a single 3'-O-acetyl group. Each of these compounds is characterized by pseudomolecular [M+Na](+) ions in the MALDI-TOF/MS spectra at m/z 763.22, 949.35, 805.22, and 991.37, respectively. The 186Da mass difference between A-type and B-type liamocins corresponds to one O-linked 3,5-dihydroxydecanoate group. HMBC NMR showed that one 3,5-dihydroxydecanoate carbonyl group is ester linked to a primary hydroxyl on the mannitol. Other long range (13)C-(1)H couplings across 1,5-ester bridges showed that the 3,5-dihydroxydecanoate groups form 1-5-linked polyester chains, similar in structure to the antibiotic substance exophilin A. Moreover, the MS analysis identified several non-conjugated poly-3,5-dihydroxydecanoate esters as minor components that are tentatively assigned as exophilins A1, A2, B1, and B2. The liamocins, and three of the exophilins, are new, previously unreported structures.

biosurfactants, Aureobasidium pullulans, liamocins, polyol oils, MALDI-TOF/MS, exophilins

There is only one chemically distinct structure:

SVGMWSMILES3D molIonize

 

CCCCCC(O)CC(O)CC(=O)OC(CCCCC)CC(O)CC(=O)OC(CCCCC)CC(O)CC(=O)OC(CCCCC)CC(CC(=O)OC[C@@H](O)[C@@H](O)[C@H](O)[C@H](O)CO)OC(C)=O

969.213 g/mol (C₄₈H₈₈O₁₉)