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Lipase catalyzed-synthesis of ascorbyl oleate was performed in ionic liquids with addition of salt hydrate pairs for water activity control. The highest yield in the synthesis of ascorbyl oleate (72%) was obtained in [BMIM][BF 4 ] in the presence of the salt pair NaI 2/0, which corresponds to a water activity of 0.3. Purity and chemical identity of 6- O -ascorbyl oleate was confirmed by 1 H and 13 C NMR analysis.

In this review, the occurrence, properties, nutritional importance and especially biotechnological methods for the production of conjugated linoleic acids (CLA) and CLA-rich lipids are summarized. Beside information from medical and nutritional studies on the biological activity of CLA, the focus is on the enzymatic synthesis of structured lipids containing CLA and the microbial synthesis of CLA.

The lipase-catalyzed synthesis of ascorbyloleate was studied using different preparations of lipases from Candida antarctica. Conversion to ascorbyloleate was influenced by the type of lipase, the carrier used for immobilization, water activity and organic solvent. The highest conversion (63%) was found using Chirazyme L-2 immobilized on carrier C2, in acetone, using methyloleate as acyl donor (4-fold excess), at water activity 0.11 and in the presence of molecular sieves.

The aim of this investigation was to obtain an efficiently immobilized intracellular lipase from Rhizomucor miehei and Yarrowia lipolytica . The activity of intracellular lipases from R. miehei and Y. lipolytica was enhanced by the addition of waste fats (beef tallow or poultry fat) to the medium and by cell immobilization on biomass support particles (BSPs, cubic particle of polypropylene or polyurethane foams). The highest intracellular activity of lipases was obtained after adding 20 and 50 BSPs to the medium of R. miehei (130.5 U) and Y. lipolytica (90.3 U), respectively. The best carrier for immobilizing intracellular lipases was polyurethane foam and the lipolytic activity of immobilized lipases was 2.1–4.3-times higher than the activity of lipases obtained from free biomass. The properties of the immobilized enzymes were very similar to the free enzymes but the immobilized intracellular lipases were more useful for the hydrolysis of waste fats. The highest reaction ratio (72%) and content of free fatty acids (68% (w/w)) in the reaction mixture was obtained after 72 h for beef tallow hydrolysis in a batch reaction with the immobilized lipases from R. miehei.

The highest yields of biosurfactants were obtained by: (i) Pseudozyma antarctica (107.2 g L−1) cultivated in a medium containing post-refining waste; (ii) Pseudozyma aphidis (77.7 g L−1); and (iii) Starmerella bombicola (93.8 g L−1) both cultivated in a medium with soapstock; (iv)Pichia jadinii (67.3 g L−1) cultivated in a medium supplemented with waste frying oil. It was found that the biosurfactant synthesis yield increased in all strains when the cell surface hydrophobicity reached 70–80 %, enabling the microbial cells to make good contact with hydrophobic substrates. The lowest surface tension of the post-cultivation medium was from 32.0 mN m−1 to 37.8 mN m−1. However, this parameter (which was also determined by a drop collapse assay) was of limited use in monitoring biosurfactant synthesis in this study. The crude glycerol was not a good substrate for biosurfactant synthesis although, in the case of P. aphidis, 67.4 g L−1 of biosurfactants were obtained after cultivation in the medium supplemented with glycerol fraction (GF2). In a low-cost medium containing soapstock and whey permeate or molasses, about 90 g L−1 of mannosylerythritol lipids were synthesised by P. aphidis and approximately 40 g L−1 by P. antarctica.

The possibility of producing monoacyloglycerols (MAGs) from poultry fat or beef tallow using selected microorganisms or enzymatic glycerolysis was established. The highest content of MAGs (16.21–17.63% w/w) in the lipids was obtained after the cultivation of Candida lipolytica on a medium with poultry fat. The concentration of MAGs in the lipids which remained in the medium was influenced by the microorganisms strains and their cultivation conditions. The yield of MAGs obtained by the enzymatic glycerolysis of poultry fat or beef tallow ranged from 3.52% to 55.10% w/w, respectively.

Aspergillus niger, Geotrichum candidum and Mucor miehei, when grown on a medium containing beef tallow or poultry fat for 5 days at 28°C, in Roux bottles, shake-flasks or fermenters, synthesized from 0.4 to 3.2 g lipids/I. The degree of fat utilization varied from 15 to 70%. The type of fat in the medium, the species of fungi and its cultivation method all influenced the fatty acid composition of fats remaining in the medium, as well as the intracellular lipids of the fungi.

The paper presents the results of investigations into the technological possibilities of controlling the transgalactosylation process of lactose in permeate after whey ultrafiltration in order to improve the efficiency of galactooligosaccharides or lactulose synthesis. The synthesis efficiency was influenced by the selection of a β-galactosidase preparation, substrate concentration and, in the synthesis of lactulose, also by the ratio of lactose and fructose added to the reaction mixture. The obtained synthesis efficiency of GOS and, most of all, of lactulose (65 g L−1), may be found satisfactory. The study also resulted in a proposed GOS or lactulose concentrates (concentrated or dried) production technology using permeate after ultrafiltration of milk or whey as lactose sources.