17 June 2018

A day in the life of a... Kew cryopreservation scientist

We step into the Millennium Seed Bank to chat to Dani Ballesteros, who oversees cryopreservation techniques that bank the world's seeds.

Cyropreservation equipment

Spanish-born Dani, 40, is an Early Career Research Fellow of the Comparative Plant and Fungal Biology department of Kew.

He is also a plant physiologist and conservation biologist that specialises in the cryopreservation (freezing at ultralow temperatures) of seeds.

Dani is married to Chantal and has a daughter also called Chantal, 5, and a son Jorge who is nearly 2.

How does your day begin at the seed bank?

I check my emails. At Kew we work with collaborators all over the world and I have work in many different institutions, so my emails are truly diverse and international.

What are you working on?

My focus now is the cryopreservation of recalcitrant seeds.

While most seeds can be stored dry in our freezers deep underground at the Millennium Seed Bank [MSB], recalcitrant seeds don’t tolerate the drying process. Special technologies such as cryopreservation (fast freezing at ultralow temperatures to avoid ice formation) are needed to ensure their long-term storage and conservation.

Any plants in particular?

Other times of the year I might work with pollen or fern spores to understand how desiccation, low temperatures and storage times affect the different types of propagules.

Acorns, conkers, chestnuts, and seeds of nearly 50% of tropical tree are recalcitrant so it’s very important that we perfect techniques to conserve these precious seeds. We never know when we will need the science or food they contain – e.g. avocado, cacao, litchis, and mango produce recalcitrant seeds.

Who do you work with?

Sometimes I work alone but often I have students with me. My supervisor is also based at Wakehurst, and we discuss our different challenges.

What kinds of techniques do you use?

I prepare the seeds under laboratory conditions, taking the embryo out and experiment with different ways of drying, cooling, thawing and growing the embryo in a test tube. I use specialist instruments to see how the water inside the embryo freezes.

Does a busy scientist have time for lunch?

Definitely! We always make time for lunch as no food or drink is allowed in the laboratories. I eat it in the staff room which is a great time to catch up with colleagues.

What does your afternoon hold?

I take the samples that I have prepared in the morning into the section of the lab where several vats of liquid nitrogen are located.

I often add a cocktail made with sugar and glycerol to the embryo, as this prevents the formation of ice, our enemy when preserving sensitive tissues at low temperatures. The embryos are placed in vials before being lowered into the vat.

Sounds like you need take a lot of care!

Liquid nitrogen freezes at about minus 196 degrees C, almost 10 times colder than a home freezer! It freezes the embryos super-fast which is what you need, again to prevent ice forming.

I wear protective googles, my lab coat and very thick gloves - the nitrogen feels like burning oil if it touches your skin! 

What time do you head home?

I leave at 5pm and am usually in charge of cooking dinner – paella is my speciality!

What are the best and worst things about your job?

The worst thing is probably the deadlines connected to securing funds for my research.

The best things are that my job is exciting, intense, demanding and diverse, plus I get to meet lots of interesting people.

I have worked and travelled all over the world and have lots of international friends. It’s an extremely rewarding career.

Plants grow in test tubes
Dani Ballesteros doing cryopreservation with sub-freezing cylinders
Dani Ballesteros doing cryopreservation with sub-freezing cylinders

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