GUIDO BOGNOLO

Independent consultant, Belgium

History is one of my hobbies, the other one is colloid chemistry in general and surface active agents in particular, so those two subjects occasionally cross path in my mind. And in my recent thoughts, among others, came the observation that while the today so unpopular petrochemical (conventional) surfactants took less of a generation to become widely established, biosurfactants are still struggling  since their early discovery over two generations ago. I admit, it is a rather trivial observation, but it elicits a less trivial question: why?

My answer is dismayingly simple: Biosurfactants DO NOT DO ANYTHING THAT CONVENTIONAL SURFACTANTS DO NOT DO.

Yes biosurfactants are easily biodegradable, but most  conventional surfactants biodegrade at rates such that they are not harmful to the environment.
Yes biosurfactants are mild, but there are mild conventional surfactants.
Yes biosurfactants are sustainable, but so are the bio-based conventional surfactants.
Yes biosurfactants have antimicrobial effects, but so do, for example, the conventional quats.
Yes biosurfactants are stable in harsh environments, but these are rarely met in real-in-use conditions, the most notable one being enhanced oil recovery, for which there are some reported  large scale trials underway in China.

The reality is that biosurfactants do not offer step changes (contrary to what the petrochemical surfactants did), just incremental improvements and  in the market dynamics incremental improvements translate in commercial success only if:

• the improvement brought about  can be perceived by the end-users
  and if yes:
• it presents  in a demonstrable cost/effectiveness advantage.

But much of the benefits of biosurfactants portrayed by their manufacturers are vague, often immaterial, subjective, and difficult to quantify, much  like the debatable “Goodwill” in certain balance sheets.
A  reproach that can be made to the producers of biosurfactants is that they have presented their products for what they are rather than for what they do or could do. As such for many years biosurfactants  have vegetated in the barren limbo of the “products looking for applications”, that rarely yields quick commercial success, rather than prospering in the fertile soil of the “the remedy for unresolved problems”. As an example certain sophorolipids are described as “low foaming”, which has an appeal on its own, but lower than if it said, for example, that in consequence “they  might be considered as an alternative to hardly biodegradable low foaming petrochemical surfactants”. Simply limiting at portraying  features leaves to the creativity of the potential user the translation of such features into useful effect, which is not guaranteed to always work. And surely not quickly.

It is pedantically repeated that the cost of biosurfactant is the obstacle to  their widespread use . This is only part of the truth: the limited availability prevented on one side to explore potential application with extensive in-use testing and on the other side  was an obstacle in the  scale-up of volume-demanding commercial realisations in the instances  when cost-effectiveness was identified.  If the volume demanded to formulate a night cream sold in a few countries can be  accommodated with the existing production volumes, it  cannot support , for example, a hair shampoo for the global market . The Evonik’s 20 kilotons per year of capacity recently bought on stream are a drop in the ocean of the 15 million tons per year or so of consumed conventional surfactants.

Associated with the volume availability is the security of supply of consistent quality ingredients: mass consumer brands cannot rely on one single production site. And last, but not least, there must be a multiplicity of suppliers, to guarantee a permanent competitive environment and prevent the establishment of monopolistic situations.

Only when acceptable price and availability are met biosurfactants could become a large scale  commercial alternative to conventional sulphonates, sulphates, ethoxylates, of course assuming that they can perform technically.

There is a conundrum here: the biosurfactant producers must have a guarantee of return on investments before raising capacity, the formulators need guarantee of supply at realistic costs before using them in large scale  brands. At some point something must  happen, lest  the deadlock   go on forever. 

There is any reason to believe that cost reduction is an ongoing objective for  biosurfactants producers, their future depends on it, and it is a certitude that there have been and there are constant incremental improvements resulting from the accumulated know-how. In certain instances cost-effectiveness must have been achieved, as biosurfactants begins to be formulated  in mass consumer products and not only in limited volume, top of the range cosmetics, that can accommodate high cost ingredients to bombast difficult-to-quantify effects. Quite frankly in many instances these seem to be just a marketing gimmick.

Biosurfactant costs have three main components:

• production plant capital: land, equipment, construction
• fermentation process   
• isolation and purification, which may include homogenization, precipitation, filtration/ centrifugation, solvent extraction and solvent recovery, drying and the variables involved are feedstock, yield/productivity, energy, chemicals, labour and sundries. 

For years much of the published research has  focused on reducing the costs of the fermentation feedstock, overlooking that these are only a fraction of the total costs, and have left  behind the other  components.  Thus there has been an overflow of academic literature on the use of any conceivable source of waste as feedstock for producing biosurfactants. All the times  the conclusions are optimistic and boringly repetitive “ This study demonstrates that XXX strain grown on YYYY waste  can produce ZZZZ biosurfactant which holds promises for its economic industrial production……..” Regrettably, so far, much of the tantalizing promises have not materialized. The generally  low  biosurfactants yields from waste feedstock result in production costs that exceeds the savings in raw materials.
Recently some excellent articles have been published, that address with  scientific rigour the resources consumption, the environmental impacts and the costs of biosurfactants production, including all three components of capital, process and purification. Apart from offering a comprehensive pictures of the impact of the variables involved, they allow the quantitative  assessment of the advantages/disadvantages of competing biosurfactant production among their self but also against the alternative biosynthesis of other chemicals,  e.g. succinic acid (1), (2), (3), (4).

Elias et al. concluded that the production model considered in their study yielded commercially viable sophorolipids based on a cost/effectiveness benchmark from another study (5).

In my opinion the production costs estimated remain high, in the range of USD 16 to 20 per kg, which is at the upper edge of cost/effectiveness. For biosurfactants to become a broad commercial success at such costs they must  be convincingly demonstrate a definite superior effectiveness compared to conventional surfactants. There is no way out.

If it is problematic that a biosurfactant can substitute a conventional surfactant for a single effect,  it has a much more chances of succeeding when it offers a combination of effects, for example  cleansing, antimicrobial and compatibility with other formulation ingredients. Having in the same product this multiplicity of features presents benefits that exceeds the simple in-use technical performance: it simplify the formulation and carries with it all the ensuing advantages, of, for instance, reducing labour and inventories of ingredients.

Research on biosurfactants has still plenty of challenges ahead, from producing strains, to enhancing yield ad feedstock conversion rate, fermentation conditions, culture media, full process optimisation, equipment design, just to quote a few. But applied research has also its challenges. Now that biosurfactants have become available in reasonable volume  there is plenty of opportunity to broaden the study of their physical-chemical properties and to translate them into consumer perceived benefits.

In this respect the cooperation agreements established between the producers of biosurfactants and the formulators of conventional surfactants is a definite positive development, as it brings together a wealth of knowledge  and create the conditions for synergism from different expertise. 

For years the world of surface active agents has seen no real  innovation, and in consequence the dominant  petrochemical surfactants have tumbled down  from specialties to commodities, with all the ensuing detrimental consequences: economic first, from money makers to cash flow generators and raw materials downloaders, and then conceptual: intellectual boredom, no attractiveness, lack of positive attention and overflow of negative publicity.

At least bio-surfactants, and for that matter  naturally occurring surfactants in general, are an injection of  hope: with all the shortcoming that have paved their development they are nevertheless  stirring the pot in an otherwise stagnant environment.  And this is at the same time challenging  and exciting.