Background 
γ-Aminobutyric acid (GABA) is a non-proteinogenic amino acid with well-documented health-promoting properties, including stress reduction, blood pressure regulation, and neuroprotective effects. Its rising demand in the functional food and nutraceutical sectors has fueled interest in sustainable and natural production methods. While microbial fermentation is a promising route, current production systems often rely on genetically modified organisms or non-food-grade processes. Filamentous fungi offer an untapped potential for natural GABA biosynthesis under food-grade conditions due to their metabolic versatility and ability to grow on complex substrates like starch hydrolysates. However, a lack of systematic optimization and understanding of the influence of media components and morphology on GABA yield limits industrial translation.

Description 
This thesis project aims to develop a food-compatible and economically viable fungal fermentation platform for GABA production using starch hydrolysate as a carbon source. The study will leverage the biocatalytic capabilities of selected food-grade filamentous fungi and explore the role of natural inducers such as corn steep liquor, onion oil, and food-derived glutamic acid sources in enhancing GABA biosynthesis.

The project will be conducted in two phases, depending on the thesis credit level:

For a 30-credit Master’s Thesis, the focus will be on strain screening, media formulation, and optimization of cultivation parameters using statistical design of experiments (DoE).

For a 60-credit Master’s Thesis, the study will be extended to scale-up in 3L and 7L bioreactors, integrating process optimization with response surface methodology (RSM) and in-depth morphological analysis.

GABA will be quantified using HPLC or LC-MS methods to ensure accuracy and reproducibility in evaluating biosynthesis efficiency.

Key Responsibilities

For 30-credit Master’s Thesis:

• Select and screen food-grade filamentous fungi for natural GABA production capability.
• Develop and optimize fermentation media based on starch hydrolysate and organic/inorganic nitrogen sources.
• Apply statistical design of experiments (DoE) to assess:
• The impact of natural inducers (e.g., corn steep liquor, onion oil, glutamic acid sources).
• The influence of culture morphology (pelleted vs. filamentous), pH range (4.5–7.5), and carbon-to-nitrogen ratio on GABA yield.
• Perform analytical quantification of GABA using HPLC or LC-MS.

For 60-credit Master’s Thesis (Extended Study):

• Conduct scale-up fermentation studies in 3L and 7L bioreactors.
• Investigate the effects of aeration, agitation, and inoculum size (2–10%) on GABA production and morphology.
• Perform morphological characterization (e.g., microscopy, image analysis).
• Utilize response surface methodology (RSM) for statistical optimization of key process parameters.

Expected Outcome

• Identification of effective food-grade inducers for GABA biosynthesis.
• Process understanding of key parameters influencing GABA yield and fungal morphology.
• Development of a robust and scalable fermentation strategy suitable for functional food or supplement applications.

Qualifications
B.Sc. Microbiology, Biotechnology, Life Sciences or equivalent. Experience in fermentation is preferred.

Terms 
1333 SEK/HP (before tax). For 30/60 credits: 39990SEK/79980 SEK

Welcome with your application!
Last day of application; 01-August-2025. Contact; abhishek.bhattacharya@ri.se or vaskar.mukherjee@ri.se. In this process, we do not request a personal letter. Instead, we ask you to answer a number of selection questions that help us better understand your skills and experience in relation to the advertised position.