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

Area of Science:

• Environmental Science
• Biotechnology
• Microfluidics

Background:

• Biochemical Oxygen Demand (BOD) is a critical parameter for assessing water quality and organic pollution.
• Conventional BOD determination methods (e.g., BOD5) are time-consuming and labor-intensive.
• There is a need for rapid, high-throughput, and onsite BOD monitoring systems.

Purpose of the Study:

• To develop and evaluate a novel bio-chip based monitoring system for efficient Biochemical Oxygen Demand (BOD) detection.
• To assess the performance of the bio-chip system in terms of sensitivity, linearity, and correlation with conventional methods.
• To demonstrate the feasibility of the developed system for onsite and high-throughput analysis of organic pollution.

Main Methods:

• Fabrication of a micro-arrayed bio-chip with micrometer-order holes using micro-machine techniques.
• Immobilization of marine luminous bacterium (Photobacterium phosphoreum) within sodium alginate gel in the micro-holes.
• Detection of bioluminescence using a chemi-imager or a custom-built onsite system with a digital camera and personal computer.
• Incubation of the chip with BOD standard solutions or sample solutions followed by bioluminescence measurement.

Main Results:

• The bio-chip system successfully detected BOD values below 16 ppm, with a linear relationship observed between 0 and 16 ppm when using 3% sodium alginate gel.
• Steady bioluminescence was maintained in the presence of standard solutions containing mineral elements.
• The onsite monitoring system demonstrated comparable performance to the chemi-imager, showing good correlation with conventional BOD5 determination.
• Simultaneous detection of BOD in multiple samples was achieved using a single chip.

Conclusions:

• The developed bio-chip monitoring system offers a promising approach for high-throughput and onsite BOD detection.
• The system's ability to provide rapid and accurate BOD measurements facilitates efficient wastewater monitoring and assessment of organic pollution.
• This technology has the potential to significantly improve water quality management strategies.