By Koldo Morante, Research Scientist

It was no more than a cigar box where I kept my memories as a child. Memories born from a collection of field bugs that offered a glimpse of my adventurous spirit. I was always captivated by stories of awe, and even more so by the way they were told. As I grew older, I began to find those stories in science itself and discovered just how thin the line between science and imagination could be.

I never knew that the steps I was taking would eventually shape me into a purification scientist. It’s one of those things I often struggle to explain to friends and family. But looking back at my story now, the path seems much clearer.

An unexpected introduction to purification

After finishing my undergraduate degree in biochemistry at Lund University, I could feel that adventurous spirit creeping up again. I began looking for a role in a research lab where I could continue my studies and found an opportunity at the University of the Basque Country.

The topic immediately caught my attention: extracting venom from sea creatures to purify and scrutinise their toxins. I thought, “That is made for me.”

And so it began, armed with a spoon, a collection beaker and a pair of gloves, I went out to confront adversity, or at least that’s how I liked to see it.

The job itself was rather simple: delicately detach sea anemones from the rocky surface and “milk” their venom - half a litre of pale scarlet liquor would do.

I would tiptoe down the rock-embedded stairs along the side of the cliff, spotting small strawberry-like lumps along the coastline. With characteristic green spots embellishing a red body, I could easily identify Actinia fragacea. With no biochemical record in the literature, my task was to flesh it out. Little did I know that this small sea creature would become my main research topic for the next handful of years.

Battling the octopus

One day, rumbling clouds brought the gentle drizzle typical of the region and season. Reaching beneath a rocky outcrop, I worked on the last specimen of the day.

As lightning flashed and thunder rolled, something suddenly grabbed me and pulled me towards the water below. Eight muscular limbs had wrapped themselves around my arm, apparently mistaking me for prey. I poked my head over the ledge to face my opponent - a giant octopus glared back at me, changing colour from natural rock to crimson red in the most marvellous display of metachrosis.

Enduring blasts of water from its siphon, I twisted my wrist to get a good hold of its limbs, determined to pull the leviathan out of its cave. But a sudden mucous secretion made me lose my grip. I was saddened that I had lost the fight, but relieved that I had come out of it alive. What seemed at the time like a one-off story would later feel like a reflection of many of the scientific obstacles still to come.

Learning what purity can tell us

Back in the lab, we purified pore-forming toxin isoforms using two ion exchange steps over a shallow salt gradient. Higher purity profiles were later achieved with the recombinant version by including a dextran-based size exclusion chromatography (SEC) step.

My work later overlapped with a postdoc at the University of Tokyo, where several discoveries followed, including high-resolution evidence of the toxin’s octameric pore architecture and its affinity for lipids and carbohydrates. The lab was highly skilled in protein crystallography, where protein purity was essential for success. Proteins were typically polished by SEC, with SDS-PAGE used as a mandatory purity check.

It was there that something about SEC particularly caught my attention. Although commonly used to separate proteins by size, its profiles could tell us much more. While some pure proteins eluted as a single SEC peak, others appeared as an array of peaks, revealing information about different conformations, stabilities and interactions of the target protein.

Purification wasn’t simply about separating one thing from another, the process itself could tell us something about the molecule we were studying.

The discovery of the pore structure also had an unexpected knock-on effect among researchers in the field. Over the following years, the protein was engineered into a nanopore for applications including DNA translocation and peptide discrimination, and was even explored as a plastic-degrading enzyme.

I was fascinated by the impact that one previously unknown, small sea protein could have on the scientific community. Looking back at my early work, I began to understand how small things can spread the seeds for something much bigger.

Moving towards translational science

Following this more technology-focused path, I later joined a group in Germany working within the Innovative Medicines Initiative to tackle drug-resistant bacteria by investigating antibiotic translocation through membrane porins. Here again, purity mattered. Porin purity was critical to reducing background noise and increasing our chances of experimental success, but something else about the experience stayed with me.

Working in a public-private consortium sparked my interest in the more translational side of science - not only understanding something scientifically, but thinking about how that understanding might ultimately be put to use.

That interest eventually led me to join Astrea Bioseparations as a Research Scientist. I was drawn to Astrea Bioseparations’ fascinating catalogue of protein-binding adsorbents. I found it particularly interesting how triazine-based ligands could be screened and designed against selected targets, including albumin fusion proteins, endotoxin, insulin and specific enzymes. A good primary capture step could improve a process and significantly reduce purification times.

At Astrea Bioseparations, I became involved in expanding the applications data for our product portfolio. Over time, it became increasingly clear that several of our protein-specific resins had hidden functionalities under particular conditions, helping to explain their role as mixed-mode ligands.

When ‘pure’ is no longer pure enough

One of the projects I worked on involved removing host cell proteins from post-affinity eluates. It was here that something I had previously considered relatively straightforward became much more complicated - what I would once have considered “pure” was no longer a valid criterion. Industry standards for therapeutic purity are remarkably high and require very sensitive assays to detect trace impurities. With ≤100 ppm a classical target threshold for host cell protein impurities, I diligently assayed my samples by ELISA, but everything I thought I knew about purity began to crumble like a house of cards.

Host cell proteins are not the only impurities in the mixture - nucleic acids, endotoxin, ligand leachate and aggregates can all compromise target purity. To make things even more interesting, the study spanned E. coli, HEK, CHO, insect and yeast cell lines, each bringing different target modalities and different obstacles. It began to feel as though science was fighting back with all its limbs, like a kraken in the sea, but I enjoyed dissecting the monster.

I found it particularly rewarding to identify the chemical conditions that could best remove host cell proteins and residual DNA, work that became characteristic of Astrea Bioseparations’ MiMode PuraBead® HL4 and HX1 resins.

What failure teaches us

All hard work bears a reward, I feel gratified when I see our work published in technical literature and shared more widely, and I enjoy knowing that we are providing solutions that can help other researchers move forward. But scientific papers and protocols can make the process look deceptively flawless, they don’t show you all the times an experiment failed or the delays incurred along the way.

Through experience, I’ve found that many failures can eventually be traced back to a root cause - often a surprisingly simple one that was overlooked. Setting sanity checks throughout a process can help identify those problems earlier and prevent future delays. That is something I would advise anyone new to the field to remember: don’t judge a book by its cover - set the right controls and check for yourself, even when projects move relatively smoothly, you also learn that experimental success is not the only measure that matters.

You need to ask whether the process can be transferred to a bigger scale and what it will cost to do so. An early “eureka!” moment can produce good scientific literature, but it may fall short as a practical solution if it cannot be scaled successfully.

The people behind the purification

Day-to-day work gives little chance for boredom. Planning, testing and discussion are the norm, and good alignment between teams can move a project forward much faster. Keeping that momentum going depends on good communication, it can get hectic, but I’m always glad when the projects bear fruit.

I’m also lucky enough to have great colleagues I can reach out to for help - and crack a joke with when needed! Those are the small things that make me feel at home and keep me open to inspiration.

Inspiration can come from behaviours, perspectives, interpretations, different angles or even the general atmosphere around you. Sometimes there is a fleeting sense that everything has come together. It rarely lasts for long, but memories have a way of trapping those moments and keeping them with us, just like those ancient stories of wonder waiting to be told in years to come. Perhaps that is why, looking back, my journey into purification doesn’t feel so unexpected after all.