What does whisky have in common with orchids and vanilla? Fragrance compounds

• Dawid Hernik has been cooperating with Prof. Filip Boratyński for many years. Under his supervision, he wrote his engineering thesis, master's thesis, and is now pursuing his doctoral degree.

Whisky lactone occurs naturally in many types of oak, and was first detected in spirits such as whisky, cognac and brandy, which are matured for long periods of time in oak barrels. Aerangis lactone is found in orchids, and piperonal is found, among others, in plants such as vanilla and violets.

– These chemical compounds are widely used as sensory additives in food, but are also used in the pharmaceutical, cosmetic and perfume industries. Things are slightly more complicated in the case of the lactones I work with, because the ones mentioned have two stereogenic centres and therefore come in the form of four stereoisomers. Simply put, each of these compounds has four forms, consisting of the same atoms but spatially differently arranged. This means that each of these stereoisomers has a different smell. Taking the example of a whisky lactone: one of them has an earthy, woody smell, while the other resembles celery – explains the doctoral student, emphasising that when obtaining lactones he not only has to obtain the chemical compound he is interested in, but also the appropriate form. – I obtain all compounds by biotransformation, i.e. a method in which I use whole microbial cells or enzymes isolated from them to obtain a product – adds Dawid Hernik. 

In his research, Dawid usually uses cultures of whole bacterial or filamentous fungal cells, to which he adds a specific compound for modification. The action of enzymes in the micro-organisms transforms it into a product. And, as the doctoral student points out, the advantages of this technique are often lower costs of producing a given compound than with chemical methods, higher efficiency, because instead of several chemical steps the whole process is reduced to a single step, and above all environmental aspects.

Dawid heard about the UPWr Doctoral School from Prof. Filip Boratyński, the then supervisor of the OrgChem students' society, which was led by... Dawid, while studying for his master's degree. – It was Professor Boratyński who told me that an interdisciplinary doctoral school was being created, and he offered me cooperation under his supervision. After giving it some thought I agreed, because after those few years at the OrgChem students' society I decided that working in a laboratory was something I wanted to do in the future. I had participated in research carried out under the students' society and participated in many scientific conferences, and some of the results were the basis for further research work carried out as part of my doctoral studies – says Dawid.

Third time lucky

Professor Filip Boratyński is Dawid Hernik's supervisor for the third time, as the doctoral student also completed his engineering thesis on the culture of lichens, and his master's thesis on the microbiological production of aromatic lactones, under his supervision. – As we have known each other for a long time, I can say that he is a very good supervisor. Of course, when it comes to research and publishing results he is very demanding, but thanks to this I know I will not have any problems defending my doctoral thesis. He always patiently answers my questions, and if I don't understand something, he explains everything step by step. There is always a good atmosphere in his laboratory and it is a pleasure to work there – says the doctoral student.

– My research collaboration with doctoral student Dawid Hernik has been going on for several years now and is going very well. In addition to writing scientific papers under my supervision, he was also involved in the OrgChem students' society. I had the pleasure of working with many ambitious and committed students when Dawid was chairman of the students' society, thanks to which it steadily climbed in the university's ranking of students' societies, eventually reaching first place. The next step in his academic career was qualifying for the then newly-established international UPWr Doctoral School – says Prof. Filip Boratyński, also telling us that Dawid is a beneficiary of the Power 3.5 programme, which is part of UPWr 2.0, through which he has received funding for his research and also has the opportunity to complete a one-year internship in a foreign research centre. He is currently conducting research for his doctoral thesis on biocatalysis in Italy, under the supervision of his second supervisor Prof. Elisabetta Brenna from Polytechnic University of Milan. 

– Professor Brenna is a very kind and helpful person. Everyone I work with at the Polytechnic University of Milan would agree, as despite her busy schedule, she always finds time to talk to and help solve scientific problems. Before leaving, Prof. Boratyński told me that I would not have to worry about anything, because Prof. Brenna will provide me with all the support I need during my internship, and indeed she does – says the doctoral student.

Asked about his future plans, Dawid Hernik emphasises that he would like to stay at the UPWr and continue his research in the Department of Food Chemistry and Biocatalysis. – It all depends on whether I obtain additional research funding from NCS or NCBR projects in the final year of my doctoral studies. If this does not happen, I will seek employment as a post-doc at other universities or in industry. I cannot also rule out the possibility of going to university abroad, which my wife strongly urges me to do, as she really likes Italy – says the doctoral student with a laugh.