Are yeasts the alternative to large-scale palm oil cultivation?

The industry is looking for sustainable alternatives to prevent millions of hectares of virgin forest from being destroyed to make way for palm oil plantations. Yeasts have attracted attention as a potential alternative. These tiny creatures have no problem breaking down organic waste. They can turn products such as sugar-rich waste streams from the paper industry, starch residues from the potato industry, or household organic waste into microbial oil.

Palm oil is used in almost every processed product you can find in the supermarket, from peanut butter and pizza to body cream and fabric softener. A few years ago, we launched a TKI project together with industry partners to investigate the potential of microbial oil as an alternative to products such as palm oil. We apply our knowledge of biology to encourage yeasts to produce oils that contain long chain fatty acids, or shorter chains, if desired. We are also working on persuading them to make oils composed of complex polyunsaturated fatty acids.

We are looking into various product categories: food, home & personal care products (including cosmetics), as well as cleaning agents and detergents. We started by trying to cultivate yeasts that produce more oil and store it in biomass. We also looked at the yield per waste stream.

The results look very promising: we have now cultivated yeasts consisting of more than half their weight (excluding water) of oil. Of course, we also wanted to know what it costs to get a yeast to produce a given fatty acid, so we calculated that too. But there is still a lot of work to be done; to compete with palm oil, we need the yeast to produce the maximum possible amount of oil per kilo of waste product.

Microbial oil in margarine and mayonnaise

So far, we have already proven that yeasts can produce a microbial oil that can easily replace sunflower oil or palm oil in margarine and mayonnaise. The next step is to modify the fermentation and purification process so that we can also isolate and use the fatty acids and glycerol from the oil.

In the short term, we mainly see opportunities for products for which consumers are prepared to pay a little more, such as food and cosmetics. The current surge in investment in the global food industry means that a breakthrough is imminent here. The cosmetics industry will not be long to follow suit.

No alternative for palm kernel oil as yet

But there are still challenges. We have yet to solve the technological puzzle of how to turn yeasts into a fully-fledged alternative to palm kernel oil. The fatty acids in this oil have a very different composition to those in standard palm oil. Palm kernel oil has a molecular length ranging between C10 and C12, rather than the C16 to C18 of standard palm oil. These shorter fatty acids are ideal for a wide range of chemical products, from surfactants in cleaning products to ingredients for personal care products. Achieving the same lengths in microbial oils is the holy grail. As yet, no yeasts that we know of can do this in an economically viable way.

Large fermentation plants needed

Another step that still needs to be taken is scaling up the process. Microbial oil will only become a serious competitor to palm oil if there are sufficient large fermentation plants. But I think this will happen: huge fermenters are already in operation that produce large volumes of organic fatty acids. The raw material is another serious challenge. Organic waste streams are often delivered in diluted form or as a solid, requiring an extra process step to make them usable for fermentation. This extra step affects the cost price of microbial oils.

Invest today and be ready in time

Despite the hurdles still to be taken, I predict a bright future for microbial oils for industrial use. By investing in research and development today, the industry will be ready in time to switch to alternative sources.

The current scale of palm oil production is simply not sustainable; millions of hectares of tropical forests have already been sacrificed for palm oil cultivation.