Brewer's spent grains (BSG), the voluminous residue after mashing, contains on dry weight basis about 40–50 % polysaccharides. For the recovery of soluble carbohydrates from BSG different physical, thermal and enzymatic treatments were used to solubilize the polysaccharides in BSG. Heating by microwave radiation to 160 °C in the presence of 0.1 M HCl released 35 % of the material in the form of reducing sugar, indicating that about 80 % of the polysaccharides were hydrolyzed. Nevertheless, 0.1 M acetic acid will even solubilize 30 % of the material as oligosaccharides on a prolonged incubation when pretreating the spent grains by extrusion cooking. A combination of the enzymes Ceremix Plus MG and CelluPract AL 70 achieved an almost 25 % release of saccharides after 4 hrs of incubation at 50 °C. A combination of extrusion cooking and enzymatic hydrolysis seems to be a very promising procedure.

A semicontinuous microbial assay for the determination of halogenated short-chain hydrocarbons in water samples was developed. The bacterium Xanthobacter autotrophicus GJ 10 forms dehalogenating enzymes, which liberate the halides in 1,2-dichloroethane as halogen ions. Cells of the organism were immobilized in chitosan beads and placed into a tube reactor, whose outlet was connected to a flow-through cell with chloride-selective potentiometric electrodes. Water samples were delivered continuously to the system, and the EMF was recorded. Both the difference in EMF between blank and sample and the velocity of the EMF change were used for calibration. The detection limit for 1,2-dichloroethane was below 0.5 mg/ L; the relative standard deviation was <10%. The effects of several parameters like flow rate and cell density were studied in detail.

Aims: To investigate properties of the proteolytic activity of a yeast cell wall lytic soil bacterium identified as an Arthrobacter species. Methods and Results: The organism was grown at pH 7AE5 and 30°C in shake flasks on media with different complex subtrates. Highest proteolytic activity assayed with azocaseine was detected in media with wheat gluten. In addition, L L-leucine, L L-alanine exopeptidase activity and esterase activity were found. The proteolytic activity showed stability up to pH 12, with a maximum at pH 11. The temperature optimum was at 55°C, but there was a loss in enzyme activity of 50% within 2 h. The proteolytic activity was inhibited by 3,4-dichloroisocumarin, whereas there was little or no effect with EDTA, pepstatin A or E64. Conclusions: The proteolytic activity is highly alkaline stable. The formation of the enzyme can be induced by media with high protein content.

Brevibacterium linens forms hydrolytic enzymes which can be used to accelerate the ripening of cheese without causing bitterness. B. linens ATCC 9172 was grown to a high cell density (50 g dry wt l-1 after 60 h) in a mineral medium containing lactic acid, soy-peptone and ammonium sulphate by applying a continuous feed of nutrients. The maximal activities of L-leucine aminopeptidase and cell-associated proteinase were 286 U l-1 and 202 U l-1, respectively. The cell-associated lipolytic activity exhibited a strong and sudden increase at 46 h, resulting in a maximum of 9.5 U g-1 dry wt; thus the volumetric productivity of proteolytic and lipolytic activity was 4220 U l-1 h-1 and 7.3 U l-1 h-1, respectively.

Cells of an Actinomycete-like bacterium, strain GJ70, with the ability to degrade several haloalkanes were used as a biological component in a discontinuous microbial bioassay for the detection of 1,3-dichloropropene and 1.2-dibromoethane in wakr. The ceils were entrapped in different matrices such as calcium alginate, carrageenan, chitosan. polyacrylamide-hydrazide and chitosan-carboxymethyl cellulose; the specific dehalogenating activity of the immobilized cells was highest with the two last matrices. By the addition of small beads of immobilized cells to a stirred sample solution and by the use of an ion selective electrode (ISE) for the quantification of enzymatically released halogen ions, the concentration of halogenated hydrocarbons could be estimated by determining the change of electrode potential within a period of 5 min. The detection limits for 1,3-dichloropropene and 1,Zdibromoethane were below 100 pg/I and 25 pgA, respectively; the relative standard deviation was c 10%. In addition, several chlorinated and brominated hydrocarbons were converted by the bacterial cells at a reduced rate e.g. 1,2-dibromopropane, 1-bromoethane, 1,5-dichloropentane, etc. Moreover, temperatures of between 20 and 40 "C did not affect the enzymatic activity of the cells, and a pH of between at 5 and 9 had little influence. Several organic substances and non-metabolizable compounds did not affect the conversion, whereas some heavy metal ions acted as inhibitors.