MechChem Africa

A proudly South African company called Biodx has developed a cost-effective disinfectant technology that comes from nature and works with nature. MechChem Africa visits the company’s Modderfontein premises and talks to CEO, Burt Rodrigues.

Biodx is on a journey to reduce society’s dependence on synthetic chemicals. “With financial support from TIA and the IDC, along with technical support from CSIR, we’ve spent the last 12 years relentlessly researching and developing antimicrobial technologies. As a result, we can now manufacture an organic, 100% biodegradable disinfectant compound that contains no chlorine, ethanol or aldehydes,” says Rodrigues.

Biodx plantCalled DECONT-XTM, Biodx’s formulation is 99.9% effective against bacterial species tested. “It is better than non-corrosive, it actively inhibits corrosion,” Rodrigues continues, adding that Biodx is now manufacturing four variants: MicrodxTM, Vitrodx®, Indusdx® and Agridx®, all of which offer groundbreaking solutions for food & beverage; medical/ pharmaceutical; industrial/manufacturing; and agricultural industries, respectively.

Born in Mozambique of Portuguese parents, Burt Rodrigues came to South Africa as a teenager and attended a technical high school in Kroonstad. After finishing matric, his parents returned to Portugal, but Rodrigues remained in the country and enrolled at Wits Technikon to study electronics.

After a year, he won an AECI Bursary to do chemical engineering at Wits. During his third year, however, he decided to get married, so joined AECI and began ‘working the benches’ at the company’s Modderfontein Laboratories. Initially, he performed analytical work on the ammonia and methanol bench, then he moved onto polymers and resins, and finally onto nitro-glycerine mixed acid (NGMA) and nitro-cotton mixed acid (NCMA) analysis.

In 1991/1992, Rodrigues joined Monroe Hickson’s Organics, which later became Akulu Marchon, as works chemist, which began his journey into detergents and first generation quaternary ammonium compounds (QACs) such as Benzalkonium chloride or alkyldimethylbenzylammonium chloride (BACs), which were widely used as disinfectants in those days. “Although now considered harmful, these are still manufactured today,” he says.

“The early BACS could neither be neutralised nor biodegraded, so they were very environmentally unfriendly. In the 50s, 60s and 70s, however, this had not yet emerged as a problem as the accumulation of pollution was not yet evident.

“Today we have to manufacture compounds that can be broken down so that they decompose/biodegrade without any long-term effects on the environment. Unfortunately, however, the older compounds are still available and they are cheap, so some people still persist in using them,” Rodrigues tells MechChem Africa.

A problem is identified

Rodrigues went on to form a small company for the supply of appropriate detergents and disinfectants for commercial and industrial applications. “We were initially supplying a relatively standard range of chlorine-based and BAC 50 products. But then enzymes started to become popular,” he relates.

Enzymes are complex molecules that act as catalysts to speed up the process of breaking down biochemical compounds such as carbohydrates, proteins and fats. They have an active site, which latches onto to a piece of the molecule being broken down. The enzyme lowers the activation energy needed to break the molecule’s bonds and, as soon as the bonds have broken, the molecule is released leaving the enzyme unchanged.

“At Baragwanath Hospital, we were supplying a BAC 50 disinfectant for general use. Then another problem was encountered: grease, fat and other debris was continually clogging up the drains and they needed a long-term solution to keep the drains clear and clean.

“We had just started to import digestive enzymes from Novozymes, the biggest manufacturer in the world, which were very effective at breaking up fats and protein cells. As well as blocking drains, waste fat is an ideal food sources for microbes, which then produce biofilm, which starts to constrict the drain further.

“So we tested and started to supply enzymes to Baragwanath to digest the fat in these drains and unblock them. This worked very well, for about a month.

“The hospital was understandably unhappy and a further investigation began, in which we discovered an incompatibility between enzymes and chlorine- or BAC-based disinfectants. So by 2001/2002, we already knew there was a problem. You could not use environmentally friendly enzymes along- side traditional chemical disinfectants,” says Rodrigues.

“This was the point at which we realised that something new was necessary. And today, our DECONT-XTM-based solutions can work alongside enzymes without destroying their digestive power,” he notes.

Further elaborating on the problems associated with BACs and chlorine-based disinfectants, Rodrigues says that although modern compounds with longer chain lengths have now been formulated that are biodegradable, the big problem with traditional disinfectant chemicals is that ‘the microbes’ develop resistance.

“Microbes and bacteria grow in colonies, feeding on the proteins and carbohydrates around them. Chemical disinfectants such as chlorine solutions and BACs kill by rupturing the bacterial cell walls because of a micro voltage charge difference. This equilibrium variation in the charge is enough to rupture the cell wall, allowing the fluid protecting the nucleus of the cell to leak out,” Rodrigues explains.

“The disinfecting compound generally remains unaffected, leaving it available to continue to attack more of the targeted bacteria. But to survive, the cells develop resistance alarmingly quickly. The microbe world is tiny, but the standard operating procedure for life applies: they eat, reproduce and die – and this cycle happens in minutes. This means that evolution happens at a vastly accelerated rate. We have measured a sample of 300 000 colony-forming units (CFUs) in the morning and by the afternoon, the sample was up to 800 000 CFUs. Some microbes will always survive a treatment, and the generations of surviving offspring therefore become increasingly resistant.

“Chlorine is widely believed to be the best water disinfectant. The maximum allowable dose in potable water, however, is 5 ppm. But the microbial load has adapted to cope with 5 ppm … read more.

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