By Mike May, PhD
For some people, melanin only serves one purpose—getting a suntan. Here, this natural biopolymer protects a person’s skin from the sun’s UV light. Similarly, melanin can protect drugs, which makes this polymer a useful delivery system for some therapies. The question is: Where should bioprocessors get the melanin?
It seems like getting enough melanin should be easy enough because all sorts of organisms (from bacteria to humans) make it. Just because melanin appears across the animal kingdom, though, doesn’t make it simple to create it at a commercial scale.
Anh TranLy, PhD, cofounder at CO2L Tech, and her colleagues once explained: “Conventionally, melanin is extracted from sepia ink or animals’ dark hair/feathers.” That’s surely not a sustainable approach. Even worse, releasing the melanin from these sources requires chemical extractions that are far from green.
Working with microbes
Alternatively, bioprocessors can chemically synthesize melanin, but the best approach might come from microbes. As a team of scientists from India recently pointed out, “Current bioprocess technologies have paved [the way] for the large-scale or industrial production of microbial melanin, which could help in the replacement of synthetic melanin.”
As one example, Zheng Wang, PhD, a research biologist at the U.S. Naval Research Laboratory, and his colleagues turned the bacteria Vibrio natriegens into melanin-making factories, but this required some tinkering.
“We developed and refined a procedure using a recombinant microbial system for the biosynthesis of melanin using the tyrosinase enzyme Tyr1 and tyrosine as a substrate,” write the researchers. ” That created a version of the bacteria that produced what the team described as “one of the highest reported volumetric productivities” of a melanin-making microbe. Consequently, Wang and his colleagues concluded: “This research represents a promising advancement toward a green, rapid, and economical alternative for the biomanufacture of melanin.”
So, these biopolymers promise to do more than tanning skin. Ongoing research is setting the stage to allow commercial bioprocessors to make as much melanin as they need for drug delivery in the future.