Characterization of the total extractable lipids of Zymomonas mobilis var. mobilis

Abstract

The cells of Zymomonas mobilis var. mobilis contained 6.3% of the chloroform–methanol–water extractable lipids (dry weight basis) and 1.5% of bound lipids. The extractable lipids were 96.8% polar lipids and 3.2% neutral lipids. The neutral lipids contained squalene, and 21 pentacyclic triterpene hydrocarbons comprised 1.4% of the total lipids. The remaining neutral lipids consisted of relatively small quantities of components tentatively identified as free fatty acids, tri-, di-, and mono-glycerides, lipoamino compounds, and pigments. The polar lipids consisted of methanol-soluble and -insoluble fractions. The methanol-soluble fraction consisted of phosphatidylethanolamine as the principal lipid and lysophosphatidylethanolamine, diphosphatidylglycerol, phosphatidylglycerol, phosphatidylcholine, dimethylphosphatidylethanolamine, and phosphatide acid as the minor lipids. The methanol-insoluble fraction consisted of glycolipoproteins comprising glucosamine, galactosamine, myristic acid, and amino acids. This glycolipoprotein fraction differed from the material isolated by standard procedures for extracting lipopolysaccharides. The lipopolysaccharide fraction, in turn, was distinctly different from the lipopolysaccharides of other Gram-negative species, since deoxyhexoses, pentoses, hexoses, aminopentose, uronic acid, phosphate, and myristic acid were the principal constitutents. There was no evidence for ketodeoxyoctulonic acid, heptoses, or hydroxy fatty acids. Hexosamines were detected in trace amounts only by colorimetric analysis.

Relationship between the cell surface hydrophobicity and survival of bacteria Zymomonas mobilis after exposures to ethanol, freezing or freeze-drying

“…1, 2) appear in agreement with a common view on the hydrophobic character of constituents in the polymorphic composition of cell envelopes from proteobacteria [11,22,26]. In fact, the range of carbohydrate concentration (7.82-47.12 g mg ¡1 dry mass) corresponds to an apparent content of LPS about 1.1-7.3% of the cell mass [11] being very comparable to that from various proteobacteria [22,26] including Z. mobilis ATCC 10988 [32].…”

Reconstruction of glucose uptake and phosphorylation in a glucose-negative mutant of Escherichia coli by using Zymomonas mobilis genes encoding the glucose facilitator protein and glucokinase

“…This is somewhat surprising when one considers the differences in plasma membrane lipids between these two organisms. Z. mobilis contains large amounts of phosphatidylcholine and an extremely high proportion of vaccenic acid (8,20 …”

Content and composition of hopanoids in Zymomonas mobilis under various growth conditions

“…A sample of dried lipid extract was treated with 72% perchloric acid at 150°C, and phosphate was determined colorimetrically after reaction with ammonium molybdate and ANSA reagent (4); diheptadecanoylphosphatidylcholine was used as the organic phosphorus standard. From the organic phosphorus content, the weight of phospholipids in the extract was estimated by using a mean phospholipid molecular mass of 730 g/mol, calculated on the basis of Z. mobilis phospholipid composition (7,30 on hopanoid content either. The organic phosphorus content, however, decreased at the highest growth rates, and as a result, the molar ratio of hopanoids to phospholipids increased from about 0.7 to between 0.9 and 1.0.…”

“…For Z. mobilis it was shown that more than 70% of the fatty acids in the phospholipid fraction is cis-vaccenic acid, which appears to be suitable for an ethanol-tolerant microorganism (7,30). The most striking result, however, was the observation of considerable amounts of neutral hopanoids (6).…”