Microbial Transglutaminases in Food and Materials Science

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Kemiantekniikan korkeakoulu | Bachelor's thesis
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Date

2024-05-10

Department

Major/Subject

Chemical Engineering

Mcode

CHEM3054

Degree programme

Aalto Bachelor’s Programme in Science and Technology

Language

en

Pages

43

Series

Abstract

Microbial transglutaminases (TGs) are crosslinking enzymes that catalyze the formation of covalent bonds between proteins. In nature, TGs participate in the microbial cell wall construction, cell division, and crosslinking of bacterial spore coats. Already, TGs have been extensively used in the food industry to enhance the texture and functionality of protein-rich foods, such as meat, dairy products, and baked goods. Furthermore, TGs are promising candidates for the development of meat substitutes and lab-grown meat, which offer sustainable alternatives to traditional livestock-based protein sources. TGs are also interesting as sustainable crosslinkers in materials science, where they could be used to enhance the mechanical properties of protein-based materials aimed, for instance, for food packaging. Despite the myriad current and potential applications for TGs, only one TG has been comprehensively characterized. This TG originates from the bacterium Streptomyces mobaraensis. Being the only TG that has been produced on a commercial scale, it is also extensively used in industry. Overall, most of the TGs that have been biochemically characterized so far originate from different Streptomyces species. However, there are a myriad of other microbial TGs present in a plethora of bacteria. Putative transglutaminases have also been identified in other microbes, such as fungi and archaea. These other TGs could potentially outperform the currently used enzyme by having an enhanced production yield in the recombinant hosts, higher activity, enhanced thermal tolerance, or being active in more alkaline or acidic reaction medias. Therefore, it is essential to characterize more TGs to fully utilize their application potential. The objective of this study was to investigate the recombinant production and activity of a TG from Bacillus subtilis (BsTG). Unlike the well-known TG from S. mobaraensis, BsTG does not require protease cleavage for activation, simplifying its recombinant production. The obtained results demonstrated that BsTG could be secreted in an active form from the yeast Saccharomyces cerevisiae. The recombinant enzyme was able to crosslink both model substrate and soy protein isolate, emphasizing its potential for further exploration.

Description

Supervisor

Hummel, Michael

Thesis advisor

Koskela, Salla

Keywords

Microbial transglutaminase, TG, bacillus subtilis, streptomyces mobaraensis, enzyme, food packaging

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https://urn.fi/URN:NBN:fi:aalto-202406254962

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[kand] Perustieteiden korkeakoulu / SCI