Rapid and onsite BOD sensing system using luminous bacterial cells-immobilized chip

• Published in: Biosensors & bioelectronics 2007-02, Vol.22 (7), p.1345-1350
• Main Authors: Sakaguchi, Toshifumi, Morioka, Yasunori, Yamasaki, Masahiro, Iwanaga, Junpei, Beppu, Kazuhiko, Maeda, Hideaki, Morita, Yasutaka, Tamiya, Eiichi
• Format: Article
• Language: English
• Subjects: Bacteria; Bio-chip; Biological and medical sciences; Biosensing Techniques - instrumentation; Biotechnology; BOD sensing; Cell-based array; Environmental Monitoring; Fundamental and applied biological sciences. Psychology; Luminous bacteria; On-chip-biotechnology; Onsite detection; Oxygen Consumption; Photobacterium; Photobacterium phosphoreum; Sewage - analysis; Sewage - microbiology; Tissue Array Analysis
• ISSN: 0956-5663; 1873-4235
• DOI: 10.1016/j.bios.2006.06.008

A BOD monitoring system based on a bio-chip which immobilized luminous bacterium in micrometer-order holes were arrayed and fabricated by micro-machine techniques, was developed. The acrylic chip (3cm×3cm) comprises nine micro-holes (diameter: 700μm or 1mm, depth: 100μm) arranged in a three by three array. Cells of the marine luminous bacterium, Photobacterium phosphoreum IFO 13896, which was grown at 15°C for 15h, were immobilized with 3% or 15% sodium alginate gel. BOD standard solutions or actual sample solution (approximately 10μl) was fallen onto the cell-arrayed chip, and then the chip was incubated at 25°C for 25min. After incubation, bioluminescence from the each hole was gray-scaled and measured by a chemi-imager or newly developed onsite-type-monitoring system using a digital camera and a mobile-type personal computer. BOD values less than 16ppm could detect by the chip, in particular, linear relationship at the concentrations between 0 and 16ppm could be observed when luminous cells were immobilized with 3% sodium alginate gel. Steady bioluminescence was observed on the chip in the presence of BOD standard solution (GGA solution) which contained mineral elements. Furthermore, simultaneous detection of BOD values in various samples could be employed in the single chip. These results showed that the monitoring system with bio-chip could achieve high-through-put and onsite BOD detection. Our newly developed onsite-type BOD detection system which was used a digital camera and a (mobile) laptop computer was applied to measure and detect organic pollution due to biodegradable substances in wastewater treatment system. The same performance as the chemi-imager system was obtained for data of bioluminescence. The obtained BOD values showed a similar correlation with that of the conventional method for BOD determination (BOD5). These results suggested for successful achievement of high-though-put and onsite detection of BOD in practical.