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Synthesis of biodiesel is performed mainly by chemical catalysis, but can also be performed by enzymatic or microbial methods, and these might play an important role in future substitution of petroleum-based diesel. To discover sustainable, economically attractive biotechnological processes for biodiesel synthesis, close cooperation between different disciplines is needed. Currently, lipases are the enzymes of choice for the synthesis of fatty acid esters (FAE) from fats and oils, yielding biodiesel with the methyl esters (FAME) as the most important product. More recently, the direct production of FAE using engineered whole cell microorganism has also been described (MicroDiesel). Current enzymatic processes are still hampered by the high costs of the biocatalyst, but significant progress has recently been made leading to the first industrial enzymatic biodiesel production. Enzymatic biodiesel production is mostly attractive because of the starting materials (waste frying oils, oils with high water content, etc.), for which conventional chemical interesterification can hardly be applied.

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.

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Protein recoveries from potato juice by ultrafiltration, polyelectrolyte-coagulation and cryoconcentration were compared. The best yield was obtained by ultrafiltration. Depending on the method of potato juice concentration, differences were observed in: foaming and emulsifying properties, wettability, swelling, and buffer capacity of preparations. The dried preparations contained a high level of proteolytic enzymes inhibitors and glucoalkaloids. Thermal inactivation of preparations before drying led to 43-48% destruction of protease inhibitors and 8 l-&9% glycoalkaloids. At the same time it was observed that thermal treatment led to distinct changes in the amino acid composition of the proteins and had an adverse effect on the properties of the dried preparations.