First bacterial galactose oxidase expands toolkit for greener drug and food ingredient production
To produce pharmaceuticals, food ingredients, and flavors and fragrances, it is often necessary to oxidize alcohols. In conventional chemistry, this transformation typically relies on harsh oxidants and elevated temperatures and generates toxic waste.
Researchers at Instituto de Tecnologia Química e Biológica António Xavier of NOVA University Lisbon have discovered the first bacterial galactose oxidase, named PsGalOx. This finding could provide a more sustainable method for producing pharmaceuticals, food ingredients, and flavors and fragrances by expanding the toolkit for greener industrial processes.
Traditional methods for oxidizing alcohols rely on harsh chemicals and high temperatures, generating toxic waste. Living organisms, such as fungi, naturally produce galactose oxidases, which can perform the same reactions on alcohols and simple sugars under milder conditions using oxygen. However, characterizing this enzyme in bacteria proved challenging due to its unusual architecture and difficulties in producing it in a soluble form.
A breakthrough came with the aid of AlphaFold, an AI system that helped researchers understand the enzyme's structure and identify changes to improve its production. The team found that PsGalOx, unlike previously characterized fungal galactose oxidases, has two nearly identical sugar-binding modules in addition to the catalytic module.
These duplicated modules have slightly different functions: one enhances sugar binding, while the other contributes to protein stability. By employing directed evolution—a technique that introduces mutations and screens thousands of bacterial colonies—they discovered that the sugar-binding modules recombined into hybrid modules, resulting in more soluble protein production.
This unexpected outcome showed that increased activity during evolution often meant more protein production rather than improved reaction speed.
Through their efforts, the researchers developed a variant of PsGalOx that is 40 to 1,800 times more efficient at processing a range of sugars and alcohols. The team plans to further engineer this enzyme for various practical applications in food, pharmaceuticals, and materials. Additionally, they aim to study the evolutionary diversity of bacterial oxidases to better understand how specificity evolved and identify robust scaffolds for developing new biocatalysts.
Written by urgent.news from Phys.org's reporting — not their text. Machine-written — may contain errors; check the original before relying on it.
