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Patent survey
Proccm Biochemistry 27 ( 1992) 49-50
Patent
Survey
This is a regular series of articles covering a selection of recent patents and patent applications from Europe, the USA and Japan.
A device and method for microbiological water treatment (US patent 5 049 266, Metz Gmbll, Mannheim, FR(;)
Mannheim
G&r and colleagues describe a microbiological water treatment system which they have designed to improve the cfficicncy of known systems. Through the mechanical separation of solids, undissolved impurities are removed from the water and kept away from the microbiological water treatment stage, whereby its effectiveness is improved. By virtue of the microbiological denitrlfication under anoxic conditions. nitrates present in the water are transformed to gaseous nitrogen and the nitrate level of the water is accordingly reduced. This is accomplished very efficiently in an overflow fixed-bed reactor. The subsequent enrichment of the water with oxygen facilitates effective microbiological nitrification under aerobic conditions in a further fixed-bed reactor. in which ammonia which has accumulated from the decomposition of biological substances containing nitrogen is oxidized through nitrite to nitrate. On the whole. this results in an efficient decomposition of nitrogen compounds contaminating the water. Subsequent to the microbiological can be nitrification, the water recirculated in partial stream for microbiological denitrificalion in order to produce an advantageous return of nitrate-containing water. The system is shown in Fig. 1. A water treatment module (14) has a sedimentation compartment (20) inlo which water is introduced under high pressure. A filter or microsieve (1) can be provided upstream of the sedimentation compartment. Above the sedimentation compartment a flooded fixed-bed reactor (22) for microbiological denitrification is
pro~esr
Biochrmislry
(27)
(I 992)-Q
located, through which water flows from below. The water travels through an overflow device (34) and a sprinkler system (36), through which dissolved nitrogen is stripped and oxygen enrichment from the air occurs, into a second fixed-bed reactor (38) for microbiological denitrification. This is a drip device, through which air flows in a chimney-like fashion. Below the second fixed-bed reactor (38) a catch basin and dram are located (44 and 54).
The Fradtz methdd and aaoaratus for detecting biological act&& in a specimen (US putent application 501123/90 and European patent application 448 923, AVL Photronics Corporation) In many applications it is necessary to determine quickly whether a specimen is contaminated by microorganisms, particularly in medical applications, the
24
49 1992 Elsevier Science Publishers Ltd. England.
Fig. 1
50 pharmaceutical industry, the food industry and in environmental protection activities. The term ‘ specimen ’ here refers to substances such as solid and liquid biological material (e.g. blood), food samples (e.g. frozen foods and preserves of canned foods), packaging material, clinical instruments and laboratory equipment (or samples taken from their surfaces), medical apparatus, first-aid and dressing material, and soil and water samples (particularly samples of drinking water). For a long time manual methods have been used in which the specimen to be assessed is placed in a culture bottle containing a liquid culture medium, and the growth of the culture is inspected visually at given time intervals. The type of presence of a microorganism is inferred from these observations by subculturing the liquid culture medium to a solid culture medium. In addition to this, some technical procedures and devices are known with which the biological activities in a sample which are caused by microorganisms may be determined, and where the CO, produced by the metabolism of the microorganism (or specifically the change in CO, content) is used as an index of biological activity. It is a known procedure, for example, to bottle the sample to be assessed with a radioactively-labelled liquid culture medium and to test the atmosphere over the culture medium for radioactive gases, providing data from which the presence of microorganisms in the sample may be determined. Measuring systems of this type are described in US patent 3 076 679 and 3 935 073. Fraatz has improved the above methods by employing the apparatus shown in Fig. 2. It comprises a sealable, optically transparent container (I) with an optode (2) attached to the inner surface (2) of its wall and bonded by a transparent adhesive layer (4). Instead of a single optode for the substance to be assessed, two or more optodes (3a, 3b and 3c) may be combined into a multilayer sensor, permitting simultaneous detection of the changes in 0, and CO, concentrations and pH for example. The individual optodes or their indicator media may be stacked in layers one above the other, or they may be imbedded in a polymer membrane in distribution. homogenous The combination of a CO, and an 0, optode into a sensor is described in European
Patent
survey
31
8 Fig. 2
patent application 0 105 870, for example. Instead of the optode (3), optodes may be provided for measuring 0,, CO,, H’ (PH). NH,‘, H,S and H,, or a specific combination of these optodes in accordance with the particular application requirements. The container contains the culture medium, which contains a carbon compound (glucose, for example) which is converted by the metabolic processes of microorganisms in the sample to metabolic product (CO,, for example), while 0, is being consumed and the pH is subject to change. As a consequence of this activity there are changes in the concentration of the metabolic product and of the initial substances, in the gas space (6) above the culture medium (5) and in the culture medium itself, which are detected by the optodes. The excitation and detection assembly (8) comprises a light source (9) a detector (11) and a two-armed light waveguide (lo), one of whose arms is coupled to the light source and the other of which is coupled to the detector. The end (12) of the light waveguide is placed flush against the exterior (13) of the wall of the container, transmitting excitation radiation towards the optodcs through the transparent wall of the container, while receiving optical signals, e.g. the fluorescence radiation emitted by the optodes. The use of a suitable filter (for example, a filter disc) at the front of the
detector will ensure that the signals are assigned to their corresponding optodes. The detector signals are transmitted to an evaluation unit (15) by way of a line (14). The change over time (e.g. of the CO, content) is thus determined and the status of the sample is indicated on a display (16). The conditions in the container necessary for the metabolic processes are maintained by a unit (17) which is principally responsible for proper temperature control of the sample, and is connected to the evaluation unit by a control lead (18). Copies of the references cited can be obtainedfrom thefollowing organizations, or at the Patent Ofices of the respective countries. European Patent OfJice, Rijsyijk, The Netherlands ; The Netherlands Patent O&e, Rijywijk, The Netherlands: The Patent Information Department of TNO, Rijswijk, The Netherlands; The International Patent Research O&-e IPRO, PO Box 16260, 2500 BG, The Ilague, The Netherlands ; UK Patents O&e, Concept House, CardifSRoad, IVewport, Gwent NP9 IRH, UK; Univentio, PO Box 16056, The Hague, The Netherlands ; USA Patents Ofice, Box 4> Patent and Trademark O&e, US Department of Commerce, Washington DC 2023 1, USA.
Patent
Survey
This is a regular series of articles covering a selection of recent patents and patent applications from Europe, the USA and Japan.
A device and method for microbiological water treatment (US patent 5 049 266, Metz Gmbll, Mannheim, FR(;)
Mannheim
G&r and colleagues describe a microbiological water treatment system which they have designed to improve the cfficicncy of known systems. Through the mechanical separation of solids, undissolved impurities are removed from the water and kept away from the microbiological water treatment stage, whereby its effectiveness is improved. By virtue of the microbiological denitrlfication under anoxic conditions. nitrates present in the water are transformed to gaseous nitrogen and the nitrate level of the water is accordingly reduced. This is accomplished very efficiently in an overflow fixed-bed reactor. The subsequent enrichment of the water with oxygen facilitates effective microbiological nitrification under aerobic conditions in a further fixed-bed reactor. in which ammonia which has accumulated from the decomposition of biological substances containing nitrogen is oxidized through nitrite to nitrate. On the whole. this results in an efficient decomposition of nitrogen compounds contaminating the water. Subsequent to the microbiological can be nitrification, the water recirculated in partial stream for microbiological denitrificalion in order to produce an advantageous return of nitrate-containing water. The system is shown in Fig. 1. A water treatment module (14) has a sedimentation compartment (20) inlo which water is introduced under high pressure. A filter or microsieve (1) can be provided upstream of the sedimentation compartment. Above the sedimentation compartment a flooded fixed-bed reactor (22) for microbiological denitrification is
pro~esr
Biochrmislry
(27)
(I 992)-Q
located, through which water flows from below. The water travels through an overflow device (34) and a sprinkler system (36), through which dissolved nitrogen is stripped and oxygen enrichment from the air occurs, into a second fixed-bed reactor (38) for microbiological denitrification. This is a drip device, through which air flows in a chimney-like fashion. Below the second fixed-bed reactor (38) a catch basin and dram are located (44 and 54).
The Fradtz methdd and aaoaratus for detecting biological act&& in a specimen (US putent application 501123/90 and European patent application 448 923, AVL Photronics Corporation) In many applications it is necessary to determine quickly whether a specimen is contaminated by microorganisms, particularly in medical applications, the
24
49 1992 Elsevier Science Publishers Ltd. England.
Fig. 1
50 pharmaceutical industry, the food industry and in environmental protection activities. The term ‘ specimen ’ here refers to substances such as solid and liquid biological material (e.g. blood), food samples (e.g. frozen foods and preserves of canned foods), packaging material, clinical instruments and laboratory equipment (or samples taken from their surfaces), medical apparatus, first-aid and dressing material, and soil and water samples (particularly samples of drinking water). For a long time manual methods have been used in which the specimen to be assessed is placed in a culture bottle containing a liquid culture medium, and the growth of the culture is inspected visually at given time intervals. The type of presence of a microorganism is inferred from these observations by subculturing the liquid culture medium to a solid culture medium. In addition to this, some technical procedures and devices are known with which the biological activities in a sample which are caused by microorganisms may be determined, and where the CO, produced by the metabolism of the microorganism (or specifically the change in CO, content) is used as an index of biological activity. It is a known procedure, for example, to bottle the sample to be assessed with a radioactively-labelled liquid culture medium and to test the atmosphere over the culture medium for radioactive gases, providing data from which the presence of microorganisms in the sample may be determined. Measuring systems of this type are described in US patent 3 076 679 and 3 935 073. Fraatz has improved the above methods by employing the apparatus shown in Fig. 2. It comprises a sealable, optically transparent container (I) with an optode (2) attached to the inner surface (2) of its wall and bonded by a transparent adhesive layer (4). Instead of a single optode for the substance to be assessed, two or more optodes (3a, 3b and 3c) may be combined into a multilayer sensor, permitting simultaneous detection of the changes in 0, and CO, concentrations and pH for example. The individual optodes or their indicator media may be stacked in layers one above the other, or they may be imbedded in a polymer membrane in distribution. homogenous The combination of a CO, and an 0, optode into a sensor is described in European
Patent
survey
31
8 Fig. 2
patent application 0 105 870, for example. Instead of the optode (3), optodes may be provided for measuring 0,, CO,, H’ (PH). NH,‘, H,S and H,, or a specific combination of these optodes in accordance with the particular application requirements. The container contains the culture medium, which contains a carbon compound (glucose, for example) which is converted by the metabolic processes of microorganisms in the sample to metabolic product (CO,, for example), while 0, is being consumed and the pH is subject to change. As a consequence of this activity there are changes in the concentration of the metabolic product and of the initial substances, in the gas space (6) above the culture medium (5) and in the culture medium itself, which are detected by the optodes. The excitation and detection assembly (8) comprises a light source (9) a detector (11) and a two-armed light waveguide (lo), one of whose arms is coupled to the light source and the other of which is coupled to the detector. The end (12) of the light waveguide is placed flush against the exterior (13) of the wall of the container, transmitting excitation radiation towards the optodcs through the transparent wall of the container, while receiving optical signals, e.g. the fluorescence radiation emitted by the optodes. The use of a suitable filter (for example, a filter disc) at the front of the
detector will ensure that the signals are assigned to their corresponding optodes. The detector signals are transmitted to an evaluation unit (15) by way of a line (14). The change over time (e.g. of the CO, content) is thus determined and the status of the sample is indicated on a display (16). The conditions in the container necessary for the metabolic processes are maintained by a unit (17) which is principally responsible for proper temperature control of the sample, and is connected to the evaluation unit by a control lead (18). Copies of the references cited can be obtainedfrom thefollowing organizations, or at the Patent Ofices of the respective countries. European Patent OfJice, Rijsyijk, The Netherlands ; The Netherlands Patent O&e, Rijywijk, The Netherlands: The Patent Information Department of TNO, Rijswijk, The Netherlands; The International Patent Research O&-e IPRO, PO Box 16260, 2500 BG, The Ilague, The Netherlands ; UK Patents O&e, Concept House, CardifSRoad, IVewport, Gwent NP9 IRH, UK; Univentio, PO Box 16056, The Hague, The Netherlands ; USA Patents Ofice, Box 4> Patent and Trademark O&e, US Department of Commerce, Washington DC 2023 1, USA.