In this issue

Biological waste for solid‐state fermentation Rodríguez Couto , Biotechnol. J. 2008, 3, 859–870 . Biological waste contains several reusable substances of high value such as soluble sugars and fibres. Direct disposal of such waste to soil or landfill causes serious environmental problems. Thus, the development of potential value‐added processes for waste is highly attractive. Biological wastes can be used as support‐substrates in solid‐state fermentation (SSF) to produce industrially relevant metabolites with great economical advantage. In addition, it is an environment friendly method of waste management. This paper from Spain reviews the reutilization of biological wastes for the production of value‐added products using the SSF technique. Mining marine shellfish wastes for bioactive molecules Hayes et al., Biotechnol. J. 2008, 3, 871–889 . Legal restrictions, high costs and environmental problems regarding the disposal of marine processing wastes have led to amplified interest in biotechnology research concerning the identification and extraction of additional high grade, lowvolume by‐products produced from shellfish waste treatments. Shellfish waste consisting of crustacean exoskeletons is currently the main source of biomass for chitin production. Chitins are very versatile biomolecules. Part A of this review aims to consolidate useful information concerning the methods used to extract and characterize chitin, chitosan and glucosamine obtained through industrial, microbial and enzymatic hydrolysis of shellfish waste. In Part B of this review the authors from the Centre of Applied Marine Biotechnology in Ireland relate in more detail some of the bioactivities and applications of chitin and shell waste by‐products. Microbial biocatalyst activity Cao‐Hoang et al., Biotechnol. J. 2008, 3, 890–903 . Many fluorescent techniques are employed to evaluate the viability and activity of microbial cells used in biotechnology. These techniques are sometimes complex and the interpretation of results opened to misunderstanding. Moreover, new developments are constantly proposed especially concerning a more accurate evaluation of the state of the cells, including eukaryotic microorganisms. In this paper, researchers from France and Vietnam aim at presenting to biotechnologists unfamiliar with fluorescence the principles of these methods and the related possible pitfalls. It focuses on probes of the physical (integrity and fluidity) and energetical (intracellular pH and membrane potential) state of the cell membrane (bacterial and yeast cells) and presents also other probes (nucleic acids, respiration...) and new technical trends.