Research projects

Here you can see some details about current and recent research projects I’m working on. My major interest is soil microorganisms and how they interact with the environment around them. These interactions are important for biogeochemical cycles, soil fertility, and plant health. The enzymes soil microbes produce can be valuable biotechnological tools, and I investigate their potential uses.

If you’re a student interested in working on a thesis or diploma project with me, visit my professional webpage for more detail and how to get in touch. You can learn about the working culture of our labspace in this article.

Soil bacteria

Biological control – or biocontrol – is the idea of using living organisms to control pests and pathogens, instead of using chemical pesticides. This can mean animals are brought in to control insect populations, or that bacteria are used to kill pathogenic fungi.

I’m interested in bacteria like Bacillus and Chitinophaga that have elegant systems for recognising and attacking fungi. They secrete proteins and other molecules that can damage potential fungal pathogens of plants. To support these anti-pathogen research goals, I’ve also investigated some pathogenic organisms, to help find new ways of inibiting their growth. A better understanding of the complex microbe-microbe interactions that are happening in the soil will help us to manage the soil microbial ecosystem a lot better, helping to make agriculture more sustainable.

Recent master’s theses

Spring 2019, KTH Division of Glycoscience. Investigating a Bacillus bacterium for deconstuction of fungal cell walls, a key mode of fungal growth inhibition.

Spring 2020, KTH Division of Glycoscience. Investigating the anti-fungal enzymology of Chitinophaga.

Recent publications

Focussed metabolism of β-glucans by the soil Bacteroidetes Chitinophaga pinensisHere we showed that C. pinensis has a very strict preference for certain types of carbohydrates. It is much better at using fungal biomass than plant biomass as a source of nutrition. This will guide future efforts to characterise enzyme activities, as it gives hints to likely enzyme substrates.

Proteomic insights into mannan degradation and protein secretion by the forest floor bacterium Chitinophaga pinensis.  We used a technique called mass spectrometry in this paper to help us identify the proteins that C. pinensis secretes when grown in different conditions. This can tell us the actual enzymes involved in different processes, and which combinations of enzymes are produced at the same time.

The impact of steroidal glycoalkaloids on the physiology of Phytophthora infestans, the causative agent of potato late blight. Plant breeders and farmers need to know what traits to select for in crop plants that are threatened by disease. The potato has suffered from blight for centuries. We investigated potato compounds called glycoalkaloids to see what effect they had on an especially nasty potato pathogen. Our results could guide potato breeders in selecting for useful traits.

Enzyme discovery

I characterise bacterial enzymes that have interesting or unusual features. Many of them have potential use in biotech applications, such as biomass deconstruction or modification. Some of this work is performed in collaboration with the Wallenberg Wood Science Centre (WWSC), a large Swedish initiative looking for new ways to use wood to make new biomaterials. The video below explains the overall goal of the WWSC: we want to find ways to use the amazing molecules inside of wood to make cutting-edge new materials. Enzymes can be useful at almost every step of the so-called wood biorefinery, as they can separate wood components, add new functionalities to them, and combine them into novel materials. Listed here below are some publications I’ve been involved in that have discovered novel enzymes with potentially very useful activities.

Recent master’s theses

Spring 2019, KTH Division of Glycoscience. Investigating Chitinophaga enzymes for biomass deconstruction technologies.

Spring 2020, KTH Division of Glycoscience. Investigating Chitinophaga enzymes for biomass deconstruction technologies.

Recent publications

Lytic polysaccharide monooxygenases (LPMOs) mediated production of ultra-fine cellulose nanofibres from delignified softwood fibres. Nanocellulose is an amazing material – it has the strength of steel if you prepare it correctly, and it can be made from waste wood and paper! The conventional processes for making nanocellulose use a lot of nasty chemicals, which we should move away from. This study showed how a single enzyme can be used to make nanocellulose from softwood, in very mild, energy-efficient reaction conditions.

Production of functionalised chitins assisted by fungal lytic polysaccharide monooxygenase. Chitin is a natural polymer found in shellfish and fungi that has great material properties and even bioactive properties, like inhibiting bacterial growth. We described a new enzyme that lets us make functional chitin with nanoscale dimensions while avoiding using the nasty chemicals that are typically required.

A GH115 α-glucuronidase from Schizophyllum commune contributes to the synergistic enzymatic deconstruction of softwood glucuronoarabinoxylan. Industrial utilisation of biomass for the production of fuel, materials, or chemicals, has to begin with separation of the biomass components. With plant biomass such as waste from the forestry and agricultural sectors, this is a very tricky challenge, because the biomass is so complex. We designed an enzyme cocktail allowing full deconstruction of one of the most complex carbohydrates in softwood.

A discrete genetic locus confers xyloglucan metabolism in select human gut BacteroidetesThis was a very cool study, and my first experience of publishing in a famous journal (Nature). The work attracted quite a lot of press attention when it was published. We investigated the enzymology of a human gut symbiont bacterium, and were the first to describe a complete deconstruction pathway for one polysaccharide in the gut. We focussed on xyloglucan, which is found in lettuce, tomato, and many other fruits and veg.