Sophorolipids are surface-active compounds synthesized by a selected number of yeast species. They have been known for over 40 years, but because of growing environmental awareness, they recently regained attention as biosurfactants due to their biodegradability, low ecotoxicity, and production based on renewable resources. In this paper, an overview is given of the producing yeast strains and various aspects of fermentative sophorolipid production. Also, the biochemical pathways and regulatory mechanisms involved in sophorolipid biosynthesis are outlined. To conclude, a summary is given on possible applications of sophorolipids, either as native or modified molecules.

This review covers the production, properties and applications of the biopolysaccharide dextran; this biopolymer can be produced via fermentation either with Leuconostoc mesenteroides strains and other lactic acid bacteria or with certain Gluconobacter oxydans strains. The former strains convert sucrose into dextran with the dextransucrase enzyme whereas the latter convert maltodextrins into dextran with the dextran dextrinase enzyme. Emphasis is mainly focused on Leuconostoc strains as producer organisms of dextransucrase and dextran types. In addition to industrial fermentation processes producing the enzymes and/or the dextrans, biocatalysis principles are also being developed, whereby enzyme preparations convert sucrose or maltodextrins, respectively, into (oligo)dextrans. The chemical and physical properties of different dextrans are discussed in detail, together with the characteristics and molecular mode of action of dextransucrase. Subsequently, useful applications of dextran and some problems associated with undesirable formation of dextran are outlined.

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Microbial metabolomics has received much attention in recent years mainly because it supports and complements a wide range of microbial research areas from new drug discovery efforts to metabolic engineering. Broadly, the term metabolomics refers to the comprehensive (qualitative and quantitative) analysis of the complete set of all low molecular weight metabolites present in and around growing cells at a given time during their growth or production cycle. This review focuses on the past, current and future development of various experimental protocols in the rapid developing area of metabolomics in the ongoing quest to reliably quantify microbial metabolites formed under defined physiological conditions. These developments range from rapid sample collection, instant quenching of microbial metabolic activity, extraction of the relevant intracellular metabolites as well as quantification of these metabolites using enzyme based and or modern high tech hyphenated analytical protocols, mainly chromatographic techniques coupled to mass spectrometry (LC-MSn, GC-MSn, CE-MSn), where n indicates the number of tandem mass spectrometry, and nuclear magnetic resonance spectroscopy (NMR)

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