Abstract: A method for producing in culture phenylalanine dehydrogenase at yields of 50+ units of enzyme per litre of culture, one unit measured as the amount required to convert one micro-mole of phenylalanine to phenyl pyrovic acid at 25.degree. C. and pH 10.8, in a growth medium comprising a nitrogen source, a buffer, phenylalanine or phenylpyruvic acid or a salt thereof at 20 mM and optionally a vitamin solution. Using phenylalanine at about 100 mM gives yields of phenylalanine dehydrogenase enzyme of 350+ units per liter of culture.

Abstract: A novel expression system is provided comprising a DNA sequence containing transcriptional and translational signals that promote the over production of recombinant proteins both in bacterial hosts (e.g., Escherichia coli) and yeasts (e.g., Saccharomyces cerevisiae). The design of the expression system lends itself to a unique strategy which allows heterologous genes to be directly cloned at a position relative to the transcription/translation signals which is optimal for expression. Particularly provided are expression cassettes comprising a sequence of the invention combined with a purpose built series of plasmids wherein the utility and efficiency of the resultant expression vectors can be demonstrated to over produce protein, particularly phenylalanine ammonia lyase (herein abbreviated to PAL), in E. coli and S. cerevisiae to levels hitherto unattainable.

Abstract: A process is described for the growth of anaerobic thermophilic heterotrophic methanogens belonging to the species Pyrobaculum islandicum and Pyrococcus furiosus to high cell densities under steady state conditions.

Abstract: Analytical apparatus includes a pyroelectric or other thermo-electric transducer element (10) in strip form. Thin film electrodes (12,14) are provided and one or more dots of reagent (16) are deposited on the transducer surface. A small amount of biological or other sample is deposited over the reagent dots which undergo selective colorimetric changes. The transducer is illuminated from below by LED light sources (24) and light absorption in the reagent regions is detected as microscopic heating at the transducer surface. The electrical signal output from the pyroelectric transducer is processed to derive analyte information.