A Brief History of Rhamnolipid Discovery, Research and Application

Rhamnolipids are produced by the bacterium Pseudomonas aeruginosa which is found naturally in soil, in water, and on plants.

Rhamnolipids were found for the first time in Pseudomonas pyocyanea grown on glucose, and was the first report of link between a sugar and a hydroxylated fatty acid. (Bergstrom S et al., Arkiv Kemi Mineral Geol 1946, 23A, 1).

More commonly, it is referenced that rhamnolipids were first discovered, isolated, and described in 1947 by F. G. Jarvis and M. J. Johnson. In 1949 their paper “A glycolipide produced by Pseudomonas aeruginosa” was published by The Journal of the American Chemical Society. (71:4124-4126.)

Bergstrom also was the first to report potential use of rhamnolipids with the discovery that rhamnolipids helped reduce the extent of tuberculosis infections. (Bergstrom, S., Theobell, H., Davide, H. 1947 On a metabolic product of Pseudomonas pyocyanea, pyolipic acid, active against Mycobacterium tuberculosis, Arkiv Kemi Mineral, Geol., 23A, no. 13, 1-15.)

In the 1950 and early 1960’s there was a lot of research on the chemical structures of bacteria, their cell walls, and interaction with lipids in forming them, but not a lot of focus on rhamnolipids.

In 1964, Morris Kates wrote a comprehensive review of bacterial lipids that reviewed lipid research up until that date and then attempted to classify bacteria based on those lipids and was the basis of much additional research.

In 1970 Norman Shaw summarized the known sources and structures of Bacterial Glycolipids.

During the 1970’s additional research was done on the pharmaceutical aspects and production of rhamnolipids and the bacteria that produced them.

Starting the late 1980’s most of the work with rhamnolipids by the famous Drs. Goran and Visnja Piljac.

Much work on P. aeruginosa and rhamnolipids was done by the team in the 1990’s by Goran Piljac, MD, PhD, DVM, and his wife, Visnja Piljac, PhD, and the Biomedical Institute of Yugoslavia, an Institute founded by the Piljacs that was part of the University of Zagreb in what is now Croatia. Dr. Piljac and his wife Dr. Visnja Piljac, based in part on Visnja’s PhD thesis, felt that there were likely significant medical applications to be found from properties derived from natural occurring strains of bacteria. The Piljac’s realized that this area of research was in its nascent stage and approached various government institutions in Yugoslavia to fund an institute dedicated to this research.

The government of Yugoslavia through the state oil company, INA, was looking for a substance to clean up oil spills that might occur on the pristine Dalmatian Coast, a popular vacation spot for Europeans. INA and other groups funded the Institute for Biomedical Sciences, Clinical Hospital Center in Zagreb Croatia. The Institute was part of the University of Zagreb Medical School. The Piljacs were the founders and directors of that Institute. The Institute employed over one hundred MDs and PhDs in various medical and biological fields. The Institute possessed some of the most sophisticated research equipment for this type of research in Europe. Through its research, the Institute gained a worldwide reputation for excellence. It worked closely with the US National Institute of Health (NIH) and, together with the medical center at the University Zagreb, was authorized to conduct research on behalf of NIH and for others, including some of the largest pharmaceutical companies in the world.

The Institute personnel traveled the world obtaining samples of bacteria and other strains for research. Thousands of strains were obtained and preserved. Initial testing was done to determine if any of the bacteria might have useful effects against tested indications. One focus, of course, was finding a natural strain that would clean oil spills without otherwise harming the environment. One tested bacteria was Pseudomonas aeruginosa. This bacterium showed some promise for cleaning oil spills but testing also showed a serendipitous result indicating some useful effects for treating psoriasis and other skin conditions. The ultimate challenge was to isolate and purify the compound among the thousands of compounds produced by the bacteria that was causing this effect. This continues to be a pain-staking process requiring highly technical skills, sophisticated scientific equipment, and a very long timeline.

Eventually, a class of compounds known as Rhamnolipids was discovered and isolated that showed beneficial effects for the treatment of diseases. In particular, one molecule was isolated and purified that had the best result for psoriasis and other skin diseases. It took the form of a di-rhamnolipid,

Although this molecule had been identified as early as 1947, no one had discovered any biomedical or biotechnological applications for the molecule nor had anyone developed the ability to purify the molecule in amounts useful for laboratory research, much less industrial production.

To date, millions of dollars have been spent to purify the various compounds.

After the break-up of Yugoslavia, the government of Croatia began serious privatizing efforts. All of the rights to all the discoveries and research of the Piljacs, as well as the thousands of collected strains were given to the Piljacs.

Although, rhamnolipids have been studied for more than fifty years, interest in rhamnolipids has increased since the 1990’s as the search for more ecological surfactants intensified. During that time a lot of interest was generated in rhamnolipids fungicidal and antibiotic properties. Rhamnolipids have been used experimentally for environmental remediation, mining, petrochemical, cosmetic, and agricultural applications.

Rhamnolipid, Inc. has done extensive research and development on production of commercial quantities of both mono-rhamnolipids and di-rhamnolipids. Through evaluation and selection, strains of P. aeruginosa have been isolated to produce rhamnolipids at high concentrations and efficiency. Rhamnolipid, Inc. has developed though natural selection and evaluation strains of P aeruginosa that produce less byproduct and selectively produce either mono- or di-rhamnolipid.

Since 1990, researchers have made great progress in successful rhamnolipid medical applications based on the Piljacs’ work, receiving a number of patents. Clinical experience in Croatia has proven significant and prolonged efficacy as a topical treatment for psoriasis, chronic wounds and as a burn wound treatment. Follow-up examinations on some of the Croatia study psoriasis participants showed they were disease free seven years after the initial treatment This technology is now owned by Paradigm Biomedical, Inc.

In 2006, Rhamnolipid, Inc. made breakthroughs allowing production, separation, and purification of rhamnolipids in industrial quantities and laboratory purities. To date, millions of dollars have been spent to develop the manufacturing process, purify and apply rhamnolipids. In 2008, Rhamnolipid, Inc. demonstrated commercial quantities of these rhamnolipids using either natural or organically certifiable processes.

These rhamnolipids can be supplied for many applications including cosmetic, pharmacological, ecological, and industrial applications and research.