32 teams applied. 7 were shortlisted to pitch. On 20 March, our start-up idea, Circulet, walked away with the £5,000 prize at the Queens’ College Entrepreneurship Society competition.
What made the moment land wasn’t just the result. For Melissa, the setting made it personal: her grandfather, Jeremias Mama Akita, studied at Queens’ College in 1945. 80 years later, his granddaughter stood in the same college, pitching a company built to keep resources in the loop. A genuine full-circle moment, the kind you don’t take for granted.
Our journey began at a meet-and-greet for the Cambridge Climate Challenge. We arrived separately, each with a different idea but the same purpose: to fix broken waste-management systems in our home countries. Melissa is from Ghana; I am from Mexico. We got talking, realised we were circling the same problem from two continents, and decided to merge our ideas and apply to the programme together. That shared idea, to formalise and democratise waste collection, became Circulet.
The problem was one I already knew intimately. I run a company in Mexico that collects used cooking oil from restaurants, so I had seen the gap up close: the oil gets recovered, but the system around it runs on cash and informal handshakes, with no reliable way to trace where it ends up or prove it was handled properly. For Melissa, whose background is in strategy consulting, the same pattern had long been evident in Ghana, where valuable material leaks away while the informal collectors who recover it go unrecognised and underpaid.
Melissa picks up the story from here.
For me, it crystallised in a classroom. In our Business and Sustainable Development class on the MBA, we were introduced to sustainability concepts in a way that made the systems behind them impossible to unsee. I pitched an idea to my project team, Rezky, Lan and Chris: use the plastic waste situation back home in Ghana as our final project. What we built was a solution that put informal collectors at the centre and incentivised households to hand over their waste. Then I went home over the Christmas break, and I saw the situation through a completely different lens. It stopped being a case study. I decided to take it forward as a passion project well beyond the classroom, and that is what birthed my determination to help solve the plastic waste problem in Ghana. It led me to start pitching the idea at other challenge events across Cambridge. Lan agreed to carry it forward with me, and later I met Felipe, who had exactly the same passion, just in Mexico.
The scale is hard to overstate. In Mexico City alone, around 80,000 food businesses generate regulated waste cooking oil every day, and there is no compliant, affordable system to manage it. That oil disappears into informal channels, undocumented, untraced, and too often polluting or simply lost.
Circulet is the operating system for circular waste. We connect restaurants, collectors, and processors into a single verified platform, making used cooking oil traceable, compliant, and valuable for everyone in the chain. We’ve built it with a cross-continental team, including Emmanuel Abalo, a PhD researcher on plastic-waste governance in Ghana, and Lan, a fellow Cambridge MBA with go-to-market strategy experience from China.
Used cooking oil in Mexico is where we start, not where we stop. The platform is built so that any waste stream can move through it, and plastic is next. That brings the idea back to where it began for me, in a Cambridge classroom, with a conversation about informal collectors and household waste. The same infrastructure that traces a litre of oil from a kitchen in Mexico City can trace a kilogram of plastic from a household in Accra. Our plan is to prove the model in Mexico, then take it to Ghana and other emerging markets where the same pattern holds.
Applying together paid off. We reached the finals of that first Cambridge Climate Challenge, were runners-up in the Trinity Hall Catalysts programme, and took part in LBS’s Launchpad pre-accelerator. Each round taught us the real lesson of the process: we spent as much time refining our story as our slides, and every time the narrative got clearer, the pitch got stronger. Get the story right, out loud, before you polish another slide.
We’re grateful to all the judges at those various pitching events for their feedback, to John Cassidy for generously funding the prize, to our mentors for their suggestions to refine our idea, and to the Cambridge ecosystem for the room to test an idea and grow through it.
What’s next is the part we’re most excited about: we’re heading to Mexico City to build the first cluster on the ground and turn a winning pitch into a working system. Queens’ was a lovely place to mark the beginning. Now the real circle, waste turned back into value and collectors brought into the formal economy, is the one we’re going to build.