NEIL BURNS

Managing Partner Neil A Burns LLC

There are over 20 companies involved in commercial activity in biosurfactants today. It is a popular and growing field. The listing of those companies in Table 1 all but guarantees that I will receive information on several more by email in response to this article. Good. Please do get in touch if I have missed you in the listing.

The history of biosurfactants in the form of Rhamnolopids spans almost 80 years and goes back to 1946 when Bergström et al. (1) reported an oily glycolipid produced by Pseudomonas pyocyanea (now P. aeruginosa) after growth on glucose, that was named pyolipic acid and whose structural units were identified as l-rhamnose and β-hydroxydecanoic acid by Jarvis and Johnson (2) in 1949. The most recent ten years however, has produced a renewed flurry of research, commercial and investment activity involving some chemical giants such as BASF, Sasol and Evonik and new investor backed startups like Holiferm, Amphistar, Locus and others. In 2024, biosurfactants are having a moment but it still remains to be seen whether and when this class of compounds can form a significant part of the surfactants market.

The case for biosurfactants is commonly understood and should require only brief elaboration. Today’s surfactant industry is built primarily on petrochemical and palm based feedstocks. Both supply chains are volatile, correlated and have other challenges around concentration of supply and, at least in the case of petrochemicals, sustainability. The search for the so-called third leg of the surfactant value chain has been underway in a serious manner since the early 2000’s and today’s biosurfactant companies often position themselves as providing the answer to that search.

Biosurfactants can be categorized in terms of molecular weight as either low (< 1,000 Daltons) or high (> 1,000 Daltons) MW. In the high MW category are polymeric biosurfactants like Emulsan and Biodisperan and particulate biosurfactants, including vesicles and whole cells. Commercial activity is minor in in this high MW category. In the low MW category are glycolipids, lipopeptides and fatty acids. We will focus primarily on glycolipids in which by far the bulk of today’s activity is taking place. Sophorolipids, rhamnolipids, mannosylerythritol A(MEL A) and trehalose lipids are the major products of interest in this class. Surfactin, which is a lipopeptide is also worth a mention. Structures of these five types of products are outlined in Figure 1.

In terms of commercial activity, the most common products today are Sophorolipids and Rhamnolipids. Sophorolipids are sold typically as a blend of the acid and lactonic forms with the carbon chain length of the fatty acid in the 16 – 18 range. Rhamnolipids are typically sold as a blend of mono and di rhamnolipids with 3 hydroxy fatty acid chains most commonly with 10 carbon atoms each.

Companies Involved

This alphabetically ordered list contains companies known to the author to be involved commercially in biosurfactants. In some cases, the company is not a manufacturer but has a venture or collaboration with a manufacturer. Where such an arrangement is known for sure, it is noted. Otherwise the assumption is made that the company is a manufacturer either in its own assets or outside assets contracted for the purpose.

Commercial Status

Despite the current excitement around biosurfactants, it is widely recognized that more work needs to be done before this product group enters the mainstream of the surfactant market. Companies are focusing on two main areas.

• Reducing Production Costs
• Expanding Market Applications

Bulk, workhorse surfactant for the large cleaning applications sell globally in the low single digits (Dollar or Euros) per Kg. Specialty co-surfactants in the high single digits and only niche surfactants get into double digits.

In a review article published in the Journal of Surfactants and Detergents titled, "Surfactants produced from carbohydrate derivatives: Part2. A review on the value chain, synthesis, and the potential role of artificial intelligence within the biorefinery concept.", Marquez et al (3), develop an economic analysis of four sophorolipid and rhamnolipid projects. The calculated minimum selling prices for the surfactants for each project, necessary to cover costs and earn a minimum return, ranged from USD 36 per Kg down to USD 6.20 per Kg. This latter for a project utilizing 46% glucose syrup as a raw material in a plant of over 8,000 MT / yr capacity. It is not clear if capital costs were taken into account properly. However, the data suggest that getting costs into the right ballpark is possible.

Further, given the quote from Evonik relating to their Slovakia plant - capex in the “low 3 digit million euro range” and capacity of “double digit metric kilotons of rhamnolipids per year”, we could read this as 2 – 300 Million capex and maybe 30,000 MT capacity. If so, to pay the plant back in 5 years, and selling at capacity, they would need to earn cash margin of say, 50 Million a year. On 30,000 MT, that’s Euros 1,600 per MT. That seems reasonable, if they can get their costs into that USD 6.20 range noted above. Even if we are off by a factor of 2, it still seems reasonable. Of course, the remaining issue becomes where to sell that 30,000 MT per year. Evonik’s close customer partnership with Unilever will be useful in this regard. Unilever has already deployed Evonik rhamnolipids in a dishwash brand, Quix.

In terms of market applications, surfactants are used in hundreds of them, many, particularly outside of cleaning, highly specialized. Biosurfactants are not drop-in replacements for any current surfactants and so formulation work is needed. That is where the value of technical service and formulation chemists comes into play. You can see from Table 1 where we have noted some of the application areas companies are focusing on. In addition to cosmetics and personal care where price points are more forgiving than in household or industrial cleaning, companies are working on food, pharma, energy, fragrance, agrochemical and materials science applications. However as noted the larger companies, like Dow, Sasol and Evonik are focusing on the traditional cleaning markets with formulation support.

Supply Chain and Process Technology

In simple terms, the supply chain starts with oils and carbohydrates (mainly sugars). The oils are understood to provide the hydrophobic part of the biosurfactant and the sugars, the hydrophilic head group. The process is fermentation in the presence of a yeast, enzyme, bacterium or algae. The major drivers of cost are: the cost of the raw materials, the yield from those raw materials and the scale at which the plant is operating.

Oil sources are well understood and include the globally traded commodities used in food and, to a much lesser extent, in existing surfactants. These are palm, soybean, sunflower, canola, olive, rapeseed as well as waste sources of oils such as soap stock.

Sugars can be obtained from a range of sources including food waste, and starch sources such as corn. Cellulosic sugars from agricultural feedstocks are also emerging. The quality of the sugar (e.g., purity and chemical structure) plays a key role in the cost and quality of the surfactant produced.

Commercial glucose is around USD 500 per MT and oils sell in the USD 800 – 1,000 per MT (palm oil) range today.

The major microorganisms used today are Pseudomonas aeruginosa, a bacterium, in the production of rhamnolipids and Starmerella bombicola, a yeast in the production of sophorlipids. Both wild-type and genetically engineered variants have been investigated. Additionally, algae have been developed as fermentation vehicles.

Non confidential details on process technology are hard to come by. However, a general outline for rhamnolipid production has been provided by Nagtode et al (4) in ACS Omega 2023 8 (13), 11674-11699. In summary it involves the following.

• The carbohydrate, oil, nutrient medium and microbe in saline solution are mixed sterile conditions
• Agitated fermentation at 30 C for up to 96 hours
• Centrifugation separates the spent microbes from the supernatant solution
• pH adjustmen of the supernatant to 2 precipitates out the rhamnolipid
• Centrifugation separates out the spent glucose in the supernatant
• Remaining rhamnolipid is washed with solvent
• Distillation under vacuum removes the solvent leaving crude rhamnolipid

Clearly cycle times could be reduced resulting in much better capex efficiency.

Outlook

Given the activity in the field, particularly in the last ten years, the author is bullish on biosurfactants. However, new chemistry takes time and money. Reconsider the capex and capacity numbers for the Evonik plant noted above and then also consider the time and money spent by the company on R&D, market and applications development since 2010 when they entered the area. The capacity deployed for biosurfactants is very small fraction of the 20 million MT / yr surfactant market; less than 1%. Think also of the development of the supply chain needed to support the industry with oils and carbohydrate of the right quality and quantity and in the right place. This will take time and money to develop.

Having said that, patient capital invested at this stage in the development of the industry may well see good results, in time. The so-called megatrends of sustainability are supporting many of the key precepts of this product class.

Biosurfactants, however, are not the only product class that can support development of a third leg of the surfactant value chain. A future review of biobased surfactants will complete the picture.