Bioprocess engineering laboratory

The task of bioprocess engineering is the design, monitoring, optimisation and scale-up of fermentations with reproducible results. As a cross-sectional technology, we draw on the knowledge of microbiology, biochemistry, computer science, analytics, sensor technology and process engineering to design, monitor and optimise fermentations.

In the bioprocess engineering teaching and research laboratory, fermentations can be carried out under controlled and sterile conditions and monitored analytically. For example, analytical methods for determining alcohol and extraction concentrations, photometric procedures, a microbial safety cabinet and close cooperation with the specialist field of food chemistry are available for this purpose.

The lab practicals take place as part of the two compulsory elective modules LT1050 Biotechnology (5th semester) and LT1041 Bioprocess Engineering (6th semester). In the lab practicals of the student training programme, we tackle new issues every year that are of interest to us in the context of ongoing research topics. The students not only use the theoretical knowledge from the biotechnology and bioprocess engineering seminars, but previous lab practicals provide the foundation and skills for the internship.

In recent years, students have worked on the following issues, among others:

• Biological control of Botrytis cinerea (grey mould rot) by lactic acid bacteria in apples to extend shelf life
• Detection methods for the biological degradation of plastics
• Screening for product formers in the in-house microbiology strain collection
• Increasing product yields (e.g. biomass, mannitol, lactic acid) by optimising fermentation conditions and media (mannitol formation)
• Characterisation of lactic acid bacteria: Determination of temperature optima, pH and ethanol tolerances, substrate uptake spectra, etc.
• Influence of cell age and cell concentration on the fermentation process
• Comparison of different operating modes (continuous vs. discontinuous)

• Beer brewing project: The project participants put the theoretical basics of beer production into practice. The underlying enzymatic processes and technological measures are used in a targeted manner to achieve a previously defined beer profile (aroma, colour, bitterness). Various fermentation by-products and thus the fermentation process can be tracked using existing analytical methods.

We are committed to utilising the diversity of metabolic potentials in native microorganisms (especially yeasts and lactic acid bacteria).

• Determination of the biochemical potential of acetic acid bacteria
• Extending the shelf life of beer via biological oxygen scavengers (biological scavengers)
• Acceleration of the main fermentation of beer through the use of a membrane bioreactor (membrane bioreactor)
• Beer from alternative raw materials (potato beer)
• Screening and characterisation of yeasts for non-alcoholic fermentations
• Determination of interactions between yeasts and acetic acid bacteria

• Microbial fuel cells use bacteria to break down organic substances and generate electricity in the process.
• Alcolyzer Beer ME: This device makes it possible to measure the alcohol content, original gravity and real/apparent extract in beer and cider.
• Brewing system for wort boiling in the beer brewing project
• Autoclave for heat sterilisation of working materials and fermentation media.
• Incubators so that our microorganisms can grow at optimum temperatures
• Clean bench / microbiological safety cabinet: Safe working under sterile conditions to protect samples and the user from contamination.
• Fibox 4 trace: Oxygen analyser that allows non-invasive measurements in samples (biological scavengers)
• Multi-point magnetic stirrer with up to 60 simultaneously stirred samples for screening tests
• Microscopes: so that we can also visualise our production organisms.
• pH meter for measuring the pH value.
• Sartocheck 4 plus: Device to determine the impermeability and permeability of membranes.
• UV-VIS spectrophotometer: This device can be used to determine the growth of microorganisms via optical density, but also to carry out various quantitative determinations (e.g. acetic and lactic acid, vicinal diketones, free amino nitrogen (FAN)).
• Centrifuges: Important for preparing samples and cell cultures