Verification of a Novel Mathematical Model for Determination of the Biomass Specific Growth Rate in Bioprocesses Using Relative Change in Biomass Measurements

Abstract:

This study presents a new mathematical model for determining the specific growth rate of biomass in biotechnological production processes, which aims to optimize the production of biotechnological products such as the advanced material polyhydroxyalkanoates. The specific growth rate is classified by the FDA as a critical process parameter that affects product quality and quantity, but is difficult for laboratory personnel to determine. Therefore, a simple and robust method for real-time monitoring and control is crucial. According to the current state of the art, the established Luedeking-Piret model for determining the specific growth rate requires the determination of the biomass as an absolute value to initialize the model and to determine two further model parameters. However, determining the biomass is time-consuming and error-prone. The new relative model replaces this value with the relative change in biomass, which can be easily recorded using standard laboratory methods such as optical density measurement. This eliminates the need for time-consuming and resource-intensive preliminary work. Despite this simplification, simulation tests have shown that the new model delivers identical results to the established model. It represents an independent, precise alternative and offers advantages in terms of handling. The results underline the model's potential to make bioprocesses more sustainable and efficient. Especially in research, material consumption, laboratory time and costs can be reduced compared to the established model. Future experiments will further investigate the performance of the new approach compared to the established model.

• Periodical: Defect and Diffusion Forum (Volume 446)
• Pages: 57-62
• DOI: https://doi.org/10.4028/p-44wCh6
• Online since: January 2026
• Authors: Mirjam Kraus*, Andrea Böhme, Gianluca Verona Rinati
• Keywords: Biomass Specific Growth Rate, Cultivation Process, Off Gas, Oxygen Uptake Rate, Real-Time Monitoring, Sustainable Bioprocesses

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