BSc and MSc Students

Future food production must become more sustainable while feeding a rapidly growing global population. Fermentation using filamentous fungi is a promising solution because it can convert plant-based substrates into nutritious, protein-rich food with a much lower environmental footprint than livestock. However, one of the key technical challenges in solid-state fermentation is the lack of reliable methods for real-time monitoring of fungal growth. Most current biomass measurement techniques are slow, destructive, and unsuitable for continuous monitoring. This project develops a non-destructive electrical sensing method that links fungal growth to changes in the electrical properties of the fermentation material. Living fungal cells can store electrical charge due to polarization effects at their cell membranes. As the amount of viable biomass increases, the system’s overall capacitance increases as well. By measuring electrical impedance, it is therefore possible to track fungal growth online during fermentation. Currently, our measurement setup can only monitor one sample at a time. The goal of this project is to scale the system by designing a multiplexing solution that enables automated measurement of multiple samples using a single impedance measurement device. The system combines a compact impedance analyzer, custom needle electrode probes for solid substrates, a digital multiplexer network for signal routing, and embedded control software for automated measurement and data handling. The final objective is to create a scalable monitoring platform that can detect normal growth behavior as well as contamination or process deviations. The project provides hands-on experience in analog measurement, embedded control, signal routing, and system integration in a real biosensing application. In addition, the project offers the opportunity to work directly with fungal cultures in the lab. This creates a unique combination of electrical engineering and living biological systems. Students will also gain insight into fermentation processes and modern food biotechnology, making the project especially interesting for those curious about the intersection of electronics, biology, and future food technologies.

1. Multiplexed Measurement Scaling: Design, build, and validate a multiplexer-based hardware system to scale bio-impedance measurements from single-channel to multi-channel operation while maintaining signal integrity and measurement accuracy. 2. Measurement Automation and Data Analysis: Develop an automated measurement and control architecture using a Raspberry Pi for hardware communication, multiplexer switching, measurement triggering, and synchronized data acquisition and storage. 3. System Understanding: Analyze how fungal growth dynamics and substrate electrical properties influence impedance signals to improve equivalent circuit models, calibration strategies, and measurement robustness.

Till Germerdonk till.germerdonk@hest.ethz.ch