Ofir Menashe

Ofir Menashe did not come to water the usual way, and he is the first to tell you so. He spent his first career in medical and pharmaceutical sales, and then at the age of 34 he did something most people only talk about, which is that he walked away from all of it to start a PhD. He went to study microbiology and biotechnology at the Technion, Israel's institute of technology, finishing around 2008 to 2009, and as he puts it he felt very old sitting in a lecture hall surrounded by people a decade younger. Israel at the time was in the middle of a serious water crisis, a long run of drought and no desalination yet, so a freshly minted microbiologist who wanted to do something useful was pulled almost automatically toward water and wastewater.

Ofir Menashe then ran into the problem that became his whole career. When he read the scientific literature, he found that bacteria already exist that can break down almost any contaminant you can name, which on paper means wastewater is a solved problem. The catch is that those wonder-microbes only behave that way in a petri dish, and the moment you drop them into a real treatment plant they get diluted, eaten by other organisms, out-competed, and they simply vanish. That gap between what works in the lab and what survives in the field is the thing BioCastle exists to close, and the way Ofir closed it is genuinely charming, because he started by thinking about bacteria as if they were employees.

Ofir Menashe describes the founding idea in a way that also explains the company's name. He decided to treat the bacteria like a worker you actually want to keep: if you want someone to do a hard job well, you give them security and decent working conditions, and a normal wastewater plant gives its best microbes neither. So he set out to build them a home, or in his own words a castle to protect those bacteria, which is literally where the name BioCastle comes from. That castle is a small structural capsule, a few millimetres across, that holds chosen bacteria behind a membrane fine enough to keep the microbes in while letting the pollutant and the nutrients flow through. The bacteria stay put, stay concentrated, and keep working.

Ofir Menashe turned that capsule into a product called the Small Bioreactor Platform, or SBP, and the operational payoff is the part an investor should care about. In a conventional biological plant you have to grow your biomass, settle it out in a sedimentation tank, recirculate it, and then deal with the leftover sludge, which is most of the plant. Because BioCastle's biomass is locked inside the capsules, all of that machinery collapses into a single chamber, with no waste sludge to handle, and the capsules last around two months before you simply top them up. You can also pick exactly which bacteria and how many go into each capsule, and run several capsule types in parallel, which lets a plant target a specific industrial pollutant the way a pharmacy targets a specific ailment.

Ofir Menashe has spent years proving the harder version of that claim, that the right encapsulated bacteria do not just trap a pollutant but mineralise it, breaking it all the way down to carbon dioxide. He started that work around 2016 on steroidal sex hormones, a notoriously stubborn class of micropollutant, and when senior engineers told him the bacteria would always prefer easier food and ignore the hormone, he ran the experiment in a test tube and showed they kept degrading the hormone anyway. That stubborn, evidence-first streak is also why he is candid about the hard part of building BioCastle, which is not the science but the selling: when your technology is so new that there is nothing to compare it to, every customer has to be educated from scratch, and that, he says, is what makes a category-creating water company slow to spread. Today Ofir runs BioCastle as its CTO, having handed the CEO seat to co-founder Gabi Wolkinson, and he also teaches the next generation of water engineers as a professor at Kinneret Academic College.

“I tried to figure the bacteria like a man. If you want to employ someone, you need to provide him some security, some condition that he will be able to work properly, and we don't provide it. So I understood that I need to invent something that will provide a castle to protect those bacteria.”

That is the whole company in one sentence: a scientist who looked at the workhorse microbes everyone takes for granted, decided they deserved better job security, and built them a castle.