Perfusion Microfermentor Integrated into a Fiber Optic Quasi-Elastic Light Scattering Sensor for Fast Screening of Microbial Growth Parameters

• Main Authors: Marco César Prado Soares, Franciele Flores Vit, Carlos Kenichi Suzuki, Lucimara Gaziola de la Torre, Eric Fujiwara
• Format: Article
• Language: English
• Published: MDPI AG 2019-05-01
• Series: Sensors
• Subjects: fiber optic sensor; microfermentor; quasi-elastic light scattering; microbial growth screening; biological monitoring
• Online Access: https://www.mdpi.com/1424-8220/19/11/2493

This research presents a microfermentor integrated into an optical fiber sensor based on quasi-elastic light scattering (QELS) to monitor and swiftly identify cellular growth kinetic parameters. The system uses a 1310 nm laser light that is guided through single-mode silica optical fibers to the interior of perfusion chambers, which are separated by polycarbonate membranes (470 nm pores) from microchannels, where a culture medium flows in a constant concentration. The system contains four layers, a superior and an inferior layer made of glass, and two intermediate poly(dimethylsiloxane) layers that contain the microchannels and the perfusion chambers, forming a reversible microfluidic device that requires only the sealing of the fibers to the inferior glass cover. The QELS autocorrelation decay rates of the optical signals were correlated to the cells counting in a microscope, and the application of this microsystem to the monitoring of alcoholic fermentation of <i>Saccharomyces cerevisiae</i> resulted in the kinetic parameters of K_M = 4.1 g/L and &#956;_m = 0.49 h^&#8722;1. These results agree with both the data reported in the literature and with the control batch test, showing that it is a reliable and efficient biological monitoring system.