The production of Biodiesel and it’s output includes multiple professional elements relating to both the physical behavior of the raw material, the types of Feedstock, the methodology of the production process and much more information accumulated during years of research and actual production experience.

Our experts have assembled questions asked most frequently and provided professional answers which we are happy to share with you.



We invite you to read through our FAQ and learn more of our business.



What is biodiesel?

Biodiesel is a natural, renewable, domestic alternative fuel for diesel engines.  It comprises mono-alkylesters (long-chain esters) derived from natural feedstocks such as animal fat, vegetable or algal oils. Vegetable oil is converted to biodiesel by a chemical (waste intensive) or enzymatic (environmentally-friendly) process called trans-esterification. Biodiesel can be used pure or blended with diesel. Biodiesel blends are usually denoted by BXX, where “XX” indicates the percentage by volume of biodiesel in the blend.

Does biodiesel differ from petroleum diesel?

Biodiesel has similar characteristics to fossil-based diesel. It can be used as a fuel for almost any diesel engine.  Biodiesel is classified as a “carbon positive” fuel. This means that biodiesel use does not increase the net amount of carbon in the atmosphere. Biodiesel therefore differs from fossil-based petroleum diesel fuel, which releases fossilized carbon into the atmosphere and contributes to global warming. Biodiesel contains zero sulphur (the main cause of acid rain). Biodiesel exhaust gases contain far fewer carcinogens and dangerous particulates than petroleum diesel exhausts, making biodiesel better for public health.

Biodiesel provides excellent lubricity to the fuel injection system. By blending biodiesel in amounts as little as 5%, the lubricity of ultra-low sulfur diesel can be dramatically improved, and the life of an engine’s fuel injection system extended.

Sources of Feedstock

The feedstock for biodiesel is 100% natural 2nd generation used cooking oil, animal fat, acid oil, and brown grease.  The greases from grease traps and waste water treatment plants cannot be used for animal feed as they exceed limits (FFAs >20%) for animal feed.  The enzymatic process can handle all kind of feedstocks and convert them to Biodiesel:


FEESCTOCK FOR BIODIESEL which can be converted to ASTM & EN Biodiesel using TransBiodiesel’s enzymatic technology include:


  • Brown Grease.
  • Acid oil (from Palm, Soybean, rape seeds and corn)
  • Animal fat category No.1.
  • Sludge palm oil.
  • Corn Oil from Bioethanol plant
  • UCO with high FFAs
  • Animal Fat (chicken, beef or  lard)


Recently non-edible Jatropha oil was used as a source of feedstocks.  A lot of work is currently being done to produce oil from algae though a commercial product is probably at least a decade away.  Cooking oil is the main ingredient in the production of biodiesel. However, the price of such edible oil keeps going up due to demand for biodiesel.  It therefore makes sense to use waste animal fat as a good, inexpensive source. However, fat has a significant disadvantage: in the conventional process, due to the high level of free fatty acids, it makes soaps instead of biodiesel.

Used-cooking oil versus Pure Virgin Oil

Virgin vegetable oil is probably the best feedstock for conventional biodiesel production process since it is pure and does not form soaps or other impurities. However, such oil is expensive.  Consumer advocates tend to recommend recycled cooking oil; the waste vegetable oil (WVO) generated by restaurants characterized with a low FFA’s values, typically below 5%.  WVO is a better candidate for biodiesel production since it is much cheaper and, if used for fuel, saves the environment from waste and contamination.

A wide variety of vegetable oils may be used including soybean, sunflower, canola, corn and peanut. Of these oils, rape seed, soybean, sunflower and canola oils are the best, followed by corn and peanut. Least desirable are coconut, palm and hydrogenated oils due to their tendency to solidify at room temperatures and may require pre-heating to liquefy.

TransBiodiesel's Enzymatic Process What is the conversion rate of biodiesel per tonne of enzyme?

By using the TransBiodiesel technology, 3,000-5,000 tons of biodiesel can be produced per ton of enzyme, depending on the purity of the feedstock oil.  In laboratory conditions/in field trials, we have even obtained a conversion rate in excess of 5,000 tons biodiesel per ton of enzyme using pure oil, liquid at room temperature.

How much enzyme do you need to make 40,000 tonnes of biodiesel?

Based on the low figure of 3,000 tonnes biodiesel/tonne enzyme, 13.3 tonnes of enzyme are required to produce 40,000 tonnes of biodiesel.

How much does the enzyme cost?

The current cost is $150-300 per kg enzyme, depending on volume. Total enzyme cost to produce 1 ton of biodiesel is between 35$-55$ USD (0.12$-0.18$ per Gallon).

What advantages does the enzyme have over conventional catalysts?

Ability to convert high-FFAs, up to 100% FFAs (i.e. lower cost) feedstocks into ASTM/EN Spec biodiesel

The Esterification/Transesterification process is done at room temperature thus saving energy

Lower feedstock cost contributes to a much lower overall enzymatic process cost. The process can convert more than 99% of any feedstock to biodiesel.

Glycerol of relatively high quality is produced (transparent, salt-free). Glycerol purity depends on FFAs content – typically 80% when yellow grease is used as a feedstock.

The Enzymatic process enables the use of Aqueous Alcohols (methanol or ethanol) with up to 20-30% water content

Where can the relevant production equipment be obtained?

The equipment can be sourced in most countries of the world country. Alternatively, TransBiodiesel can manufacture it in Israel utilizing its engineering arm Meptagon and it can be shipped to the customer anywhere in the world.

Can TransBiodiesel assist with the plans for the reactor?

Yes, TransBiodiesel (with Meptagon, our Engineering Arm) can assist in all relevant aspects of production planning.

Is the enzyme process ready-for-use now?

The enzyme is ready for use at any scale either batch-wise or in a continuous process.

What negative reactions does the enzyme process give?

The enzyme should not be exposed to temperatures above 40°C, or to extreme low and high pH values.

What process conditions are required?

Reaction ingredients ratio (oil:methanol or oil:ethanol) of 1:5 on molar basis.   The reaction is performed at 35°C – 40°C. The biocatalyst can be run in a continuous reactor (CSTR).  The biodiesel produced requires post-treatment in order to meet ASTM or EN specs.

What are the installation costs?

Capital cost for the enzymatic process is similar to the capital cost required for a conventional biodiesel plant of similar production capacity.

What water content is acceptable?

Our transesterification/esterification biocatalysts are tolerant towards the presence of water. Oil feedstock containing up to 10% water can be treated with our enzymes.

Is it preferable to remove water from the feedstock or will it separate out in the glycerol phase?

Water may be left in the feedstock due to the moisture tolerance of transesterification/esterification reactions. Water is best removed in the glycerol phase.

What % methanol is added to the feedstock?

The per cent of methanol added depends on the FFAs of the feedstock. For feedstock of zero FFAs, 15% methanol by weight is required whereas higher than 15% FFAs feedstock requires approximately 20% methanol. Excess of methanol can be flashed out and reused in our process regardless of its water content.

What is the filtration requirement for particulates prior to the reactor beds?

Currently, biodiesel is filtered down to 2 micron. Our intention is to filter up front and avoid fouling of the resin beds, etc. It is preferable to filter down to 5 micron prior to the enzymatic reaction. This avoids blockage of the enzyme bed.

What is the price of glycerol?


The price of glycerol varies according to quality. Glycerol derived from our enzymatic process is in the range $200 – $400 USD/ton depending on purity/application.

Some high FFAs oils are almost black. What will be the color of biodiesel and glycerol after the process? Is it necessary to go through a bleaching step?


The color will remain the same after enzymatic treatment. Hydrophilic color materials will move to the glycerol phase and hydrophobic color materials will remain in the biodiesel phase.

What quality/color glycerol is obtained?

The quality is very high. Only small amounts of water and methanol are present in the glycerol, which is colorless. (Photos can be provided.)


What is the conversion efficiency of the enzyme catalyst in biodiesel production?

1kg of biocatalyst will produce at least 3 tons of biodiesel, and maybe up to 5 tons depending on oil quality. The enzyme resin must be changed once every 6-10 months of operation depending on the feedstock quality.

What wastes are generated in biodiesel and glycerol?

There are no wastes from the process. The enzyme resin may be incinerated or landfilled. The biodiesel and glycerol phases will maintain the non-fatty acid materials. Therefore, both phases should undergo physical treatment to bring them to the required specifications.

Does FFAs level have an effect on conversion efficiency?

Increasing feedstock FFAs increases conversion efficiency. TransBiodiesel’s biocatalyst possesses simultaneous esterification and transesterification activities.

What are the oil raw material requirements at industrial scale?

The waste oil needs to be free of solids, filtered down to 1-5 microns (preferably 1 micron).  Note, particle size is not the relevant measure for determination of solids content.  Solids may plug the reactor screen. If solids pass through screen they will go out with glycerol.  Filtering of waste oils and grease is often problematic therefore, centrifugation is recommended.

Is there any soap formation using the enzyme-based catalyst? Are there any other by-products in addition to the glycerol?

There is no soap formation but there is a water formation.

Are there any Cold Soak requirements?

The enzymatic process does not take care of Cold Soak.  Cold Soak is a function of crystal (sterols) formation and is dependent on characteristics of the feedstock.  Animal oil is worse than soy oil. There are several post-treatments to improve Cold Soak.


What issues of concern are there when using fat as a feedstock?

Animal fat contains high levels of free fatty acids (FFAs). The conventional chemical process utilizes sodium methylate (NaOCH3) or sodium hydroxide/methanol as catalysts. Using these catalysts, FFAs are converted to the sodium salts of fatty acids (commonly referred to as “soap”).  By contrast, TransBiodiesel’s enzymatic process is natural and doesn’t form soap. The enzyme converts both the oil (triglycerides) and FFAs to biodiesel.