Juri Sudheimer About Plant-Based Engine Oil Instead of Petroleum: How Biosynthetics Help Reduce Emissions and Protect the Planet

When we hear the phrase “vegetable oil in an engine,” the imagination jumps to a bottle of sunflower oil from the kitchen being poured into a car’s oil filler neck. For any engine specialist, this is a nightmare: stuck piston rings, sludge that looks like plasticine in the crankcase, and a full engine rebuild after just a few thousand kilometers. But modern tribology—the science of friction—has moved far beyond culinary experiments.

Today’s “green” lubricants are not crude plant extracts, but high-tech products of organic synthesis. The industry is on the brink of a paradigm shift: petroleum is becoming too dirty and too expensive to refine under new environmental standards such as Euro-7, while gas-to-liquid (GTL) and petroleum-based synthetics (PAO) have largely reached the limits of their performance.

Biosynthetics are not just a nod to environmental fashion. They are an attempt by engineers to outsmart physics by creating oils that adhere to metal surfaces better than any petroleum product, yet burn cleanly without producing soot. Let’s take a closer look at how algae and soybeans are turned into base stocks for racing cars, who is driving this development, and why it matters for the air in our cities.

Contents

• The chemistry behind it: why plants work in internal combustion engines
• What oils are made from: from soy to algae
  • Traditional crops: soy and rapeseed
  • Castor oil: the gold standard
  • Algae: the hidden champion
• The market and key players: who is already bottling “green” oil
• Costs and forecasts: how much it costs now and what to expect in 10 years
• Urban ecology: emissions and leaks
• The downside: why we haven’t fully switched to bio-oils yet
  • Issue No. 1: water sensitivity (hydrolysis)
  • Issue No. 2: seals and elastomers
  • Issue No. 3: incompatibility
• Final conclusions

The Chemistry Behind It: Why Plants Work in Internal Combustion Engines

To understand why bio-oils work, we need to look at them on a molecular level. Traditional engine oils (mineral or hydrocracked) consist of hydrocarbons derived from crude oil. These molecules are generally non-polar—in simple terms, they are neutral toward metal. They stay on engine parts thanks to viscosity and pressure, but once the engine stops and oil drains back into the sump, the upper parts of the engine are left almost dry. This is why up to 70% of engine wear occurs during cold starts.

Esters and estolides behave differently—and it’s important not to lump everything together. Esters are a classic synthetic base stock, known since the 1930s–1940s (originally developed in Germany for jet aviation and produced from coal). Esters are formed by a reaction between an alcohol and an acid, and the acid does not have to be a fatty one. Estolides, however, represent a genuinely new “plant-based” perspective. They are complex esters of high-molecular-weight fatty acids and are structurally very similar to PAOs (polyalphaolefins).

The key point is that these molecules are polar—they have an electrical charge (a dipole moment). As a result, they act like billions of microscopic magnets. An oil film based on such molecules literally “sticks” to metal surfaces of cylinders and camshafts at an electrochemical level.

What does this mean in practice?

1. Ultra-strong oil film. Even if the hydrodynamic oil wedge breaks down, polar molecules remain on the metal, preventing dry friction.
2. High viscosity index. Petroleum oils thicken in cold weather and thin out in heat. To compensate, polymer viscosity improvers are added—but these degrade over time. Plant-based components naturally have a high viscosity index, requiring fewer improvers and allowing the oil to retain its properties longer.
3. Improved heat transfer. Esters have higher heat capacity, allowing them to remove heat from hot pistons more effectively.

In the past, the main drawback of plant-based base stocks was oxidative stability: conventional vegetable oils oxidize and go rancid. Modern technologies now “cut out” the weak links in fatty acid molecules (double bonds) and replace them with more stable structures. The result is a base oil that can outlast low-cost petroleum semi-synthetics.

Comment by Juri Sudheimer: Why the Industry Needs Biosynthetics

We asked Juri Sudheimer, who works on the practical adaptation of modern base oils and formulations within the Mannol brand, to comment on the subject. According to him, interest in biosynthetics is driven not by environmental fashion, but by the technological limits of traditional petroleum base stocks.

He notes that classic mineral oils—and even highly refined petroleum oils—are increasingly unable to meet the requirements of modern engines. They either demand ever more complex additive packages or fail to deliver stable performance across wide temperature and load ranges. Biosynthetic bases, by contrast, allow engineers to “build” a molecule with the desired properties from the outset—from polarity to volatility—making them a powerful tool for the future development of engine oils.

What Oils Are Made From: From Soy to Algae

The raw-material base for biolubricants is broad and not limited to food crops. The task of chemists is to obtain specific fatty acids from which the ideal lubricant molecule can then be assembled.

Traditional Crops: Soy and Rapeseed

In the United States, soybeans became the industry’s pioneer. Farmers long sought applications for surplus harvests, and agricultural lobbying helped spur research. Soybean oil is rich in linoleic and oleic acids. Through chemical modification (epoxidation or re-esterification), soy can be converted into base oils well suited for hydraulic systems and agricultural transmissions.

In Europe, rapeseed dominates. Oils based on Rapeseed Methyl Ester are often used in two-stroke engines and chainsaws, where the lubricant is expelled into the environment—here, biodegradability is critical.

Castor Oil: The Gold Standard

Castor oil, derived from castor bean seeds, is legendary in motorsport and is the thickest of vegetable oils. Veterans still remember the smell of Castrol R at racing circuits. Its exceptional lubricity comes from ricinoleic acid (incidentally, sebacic acid used in classic ester production is also derived from castor oil). The historical drawback of castor oil was heavy deposit formation. Today, genetic engineering has produced special castor varieties whose oil lacks these disadvantages while retaining extraordinary “stickiness.” This is no longer pharmacy-grade castor oil, but a sophisticated feedstock for premium base oils.

Algae: The Hidden Champion

This may be the most promising direction of all. Soy and rapeseed require arable land, water, and fertilizers, competing with food production. Microalgae, by contrast, are grown in bioreactors. Companies such as TerraVia (formerly Solazyme), working with global players like Unilever, have shown that algae can be “programmed” to produce oils with specific chemical profiles. Oil yield per hectare of algae cultivation is many times higher than that of soy. Moreover, algae absorb CO₂ as they grow, making production carbon-neutral even before the oil reaches the bottle.

The Market and Key Players: Who Is Already Bottling “Green” Oil?

If you think bio-oils are confined to small laboratories, think again—major industry players are already involved.

• Fuchs. The German group is one of the pioneers. Its Planto line is well known in industrial applications (hydraulics, gearboxes) and is increasingly entering the engine oil segment for specialized equipment.
• TotalEnergies. Actively developing biolubricants, with strong positions in marine and agricultural oils where leaks are especially critical.
• Motul. The legendary 300V series is ester-based. While marketed as a racing product rather than an eco solution, ester content can reach 20–30%. Motul also offers lines certified as biodegradable.
• Castrol. Conducts R&D in partnership with biotech companies, creating products using recycled plant-based waste.
• Novvi. A U.S. company behind the revolutionary SynNova base oils—100% synthetic products made from sugar (plant feedstock) that outperform traditional PAOs. Chevron is among Novvi’s investors, underscoring the seriousness of this approach.
• Biosynthetic Technologies. Produces estolides, a new class of biosynthetic base oils whose potential is still being evaluated. Their products have already received API certification, opening the door to mass-market engines.

Costs and Forecasts: How Much It Costs Now and What Comes Next

At present, biosynthetics are expensive. Even simple carboxylic acid esters cost more than PAOs, which is why their use is limited. Polyol esters, produced using fatty acids, can be three to four times more expensive than carboxylic esters. Estolides appear to fall into a similarly high price category. The reasons are complex logistics, expensive feedstocks, and relatively small production volumes compared to massive refineries.

In terms of market size, the global biolubricants market is currently estimated at USD 2.8–3.5 billion. This is tiny compared to the overall lubricants market exceeding USD 160 billion—but it is growing faster than any other segment.

Today, fully ester-based oils are mainly used in aviation (turbine oils), gas-compressor turbines, and military applications (for example, submarine compressors). In civilian automotive oils, esters are typically used as additives, making up around 3%.

Forecasts

• In 3 years: growth to around USD 4.2 billion, driven primarily by legislation (Environmentally Acceptable Lubricants, EAL) in the U.S. and EU mandating biolubricants in marine and forestry applications.
• In 5 years: technologies from companies like Novvi may reduce production costs of bio-base stocks to the level of traditional synthetics (PAO). The market could reach USD 5.5 billion, with more “bio-based” oils appearing on regular store shelves.
• In 10 years: bio-components are expected to make up 15–20% of passenger-car engine oils. Total market volume may exceed USD 7–8 billion.

By then, petroleum-based oils will be more expensive due to carbon taxes, and price parity will be achieved not by cheaper biosynthetics, but by costlier oil-based products.

Urban Ecology: Emissions and Leaks

How exactly does oil help reduce emissions? There are two aspects: an obvious one and a hidden one.

The obvious aspect is biodegradability. Vehicles inevitably lose oil—through leaking seals, damaged sumps, or oil consumption. Petroleum oil that enters soil or stormwater systems remains toxic for years. Esters (regardless of whether they are derived from coal or plants) that meet OECD 301B standards can biodegrade by 60% or more within 28 days. For municipal equipment operating in parks and residential areas, this is critical.

The hidden—and most important—aspect is the impact on exhaust emissions. This is where biosynthetics truly shine.

Juri Sudheimer on Environmental Impact

Commenting on the environmental dimension, Juri Sudheimer emphasizes that the main contribution of biosynthetics to “cleaner cities” lies not so much in biodegradability, but in indirect emission reductions. Lower friction, more stable viscosity, and low volatility directly affect fuel consumption and the lifespan of exhaust aftertreatment systems.

In modern engines, oil is no longer just a lubricant—it has become part of the vehicle’s environmental system. Biosynthetics deliver an effect that cannot be achieved solely through improved catalysts or filters: engines stay cleaner longer, and emissions remain stable throughout their service life.

• Lower friction = less CO₂. Thanks to the polarity of ester and estolide molecules, these oils achieve extremely low friction coefficients (below 0.05). Less friction means less energy wasted, improving fuel economy by 3–5%. Across a megacity, this translates into thousands of tons of unburned fuel.
• Low volatility and NOACK. Biosynthetics have very low evaporation losses. Conventional oils evaporate in hot engines; vapors enter the intake, burn, and form ash that clogs catalysts and diesel particulate filters (DPFs). Bio-oils evaporate far less.
• Clean combustion. Bio-base oils contain virtually no sulfur or aromatic hydrocarbons. When they do enter the combustion chamber, they do not form hard abrasive particles or sulfate ash, extending the life of exhaust aftertreatment systems. A healthy catalyst means cleaner air in traffic jams.

The Downside: Why We Haven’t Fully Switched to Bio-Oils Yet

Let’s be honest: if biosynthetics were perfect, Exxon and Shell would have shut down oil rigs long ago. The technology still has growing pains.

Issue No. 1: Water Sensitivity (Hydrolysis)

Esters are highly attracted to water. When moisture enters the crankcase (winter condensation), some ester types can break down into acid and alcohol, with acids corroding engine components. Modern developments, including advanced estolides, largely eliminate this issue, but older formulations still exist.

Issue No. 2: Seals and Elastomers

Polar molecules are so active that they can penetrate elastomers (gaskets and seals). Old rubber may swell and weaken; new materials may shrink. Manufacturers must carefully balance additive packages to control this interaction. Pouring pure bio-oil into a 1980s Lada is a sure way to have every seal leaking within a week.

Issue No. 3: Incompatibility

You cannot simply top up a mineral oil with a biosynthetic one. In some cases, this can cause precipitation or foaming. Switching to bio-oil requires a complete system flush.

Final Conclusions

The lubricant industry is undergoing a quiet revolution. While headlines focus on electric vehicles, chemists are extending the life of internal combustion engines, making them cleaner and more efficient.

Plant-based engine oil is no longer an experiment—it is a reality for owners of modern equipment willing to pay for engine longevity and a cleaner conscience. Biosynthetics have evolved from finicky castor oil into highly stable molecular “building blocks” that outperform petroleum in every respect except price. But as urban environmental regulations continue to tighten, we may soon have no choice—and that may be for the best: engines will last longer, and the air will become just a little clearer.