Def Leppard, “Pour Some Xylose on Me!!!”

Def Leppard, "Pour Some Xylose on Me!"
Def Leppard, “Pour Some Xylose on Me!”


Sounds like the title to a Def Leppard song doesn’t it? Well, it’s not but, what it is, is the sustainable biomass answer to the fuel needs of our vehicles.

Introducing Yi-Heng Zhang’s Xylose Miracle

Yi-Heng Zhang’s also known in the US as Y.H. Percival Zhang has successfully extracted Hydrogen gas from plants by using a vitro synthetic enzyme cascade to break down the plants in a manner that is nearly 100% efficient.

Previously, there were a few known methods of extracting H2 from plant matter and through separation of water.  Water is the most expensive extraction method but simple to do in a home experiment where one sticks a couple of wires onto the end of  batter and sticks the other end into the water which causes the water to break into two parts Hydrogen and one part Oxygen (H20àH2 + O).

The other methods of generating H2 from biomass include using microbial fermentation, enzymatic decomposition, gasification, steam reforming, and aqueous phase reforming.

Introducing the Xylose Failures of the Past

Biomass is biomaterial from living, or recently living organisms, most often referring to plants or plant-derived materials.

Fermentation typically refers to the conversion of sugar to acids, gases and/or alcohol using yeast or bacteria. The science of fermentation is known as zymology. The process is often used to produce wine and beer.

Enzymatic decomposition is the process of using enzymes to break down biological material. Enzymes are large biological molecules responsible for the thousands of chemical interconversions that sustain life. They are highly selective catalysts, greatly accelerating both the rate and specificity of metabolic reactions, from the digestion of food to the synthesis of DNA. Most enzymes are proteins, although some catalytic RNA molecules have been identified. A Catalyst increase in the rate of a chemical reaction due to the participation of a substance unlike other reactive substances, a catalyst is not consumed. A catalyst may participate in multiple chemical transformations.

Gasification is a process that converts organic or fossil based carbonaceous materials into carbon monoxide, hydrogen and carbon dioxide. This is achieved by reacting the material at high temperatures (>700 °C), without combustion, with a controlled amount of oxygen and/or steam. The resulting gas mixture is called syngas (from synthesis gas or synthetic gas) or producer gas and is itself a fuel. The power derived from gasification and combustion of the resultant gas is considered to be a source of renewable energy if the gasified compounds were obtained from biomass.

Steam Reforming of natural gas or syngas sometimes referred to as steam methane reforming (SMR) is the most common method of producing commercial bulk hydrogen as well as the hydrogen and until Percival Zhang came along it was also the least expensive method. At high temperatures (700 – 1100 °C) and in the presence of a metal-based catalyst (nickel), steam reacts with methane to yield carbon monoxide and hydrogen. These reactions can be reversed.

CH4 + H2O ⇌ CO + 3 H2

Additional hydrogen can be recovered by a lower-temperature gas-shift reaction with the carbon monoxide produced. The reaction is summarized by:

CO + H2O → CO2 + H2

The first reaction is strongly endothermic (consumes heat), the second reaction is mildly exothermic (produces heat).

Aqueous Phase Reforming The water portion of a system consisting of two liquid phases is the property of liquids to mix in all proportions, forming a homogeneous solution. One phase is primarily a water phase, and the second is a liquid immiscible with water.  The term immiscible applies also to other phases (solids and gases), but the main focus is usually on the solubility of one liquid in another. Water and ethanol, for example, are miscible because they mix in all proportions. In this case, the process is used to produce Hydrogen.

Unfortunately, all of these methods suffer from low yields and are therefore costly to use for H2 production on a large scale.

Percival Zhang’s discovery is a game changing find. It means that we will be able to produce hydrogen cheaply from plant matter. It is also a renewable and sustainable because it takes as much carbon dioxide to grow the plants that the hydrogen is made from as it does to produce the hydrogen.

Net CO2 produced= 0!

Another great thing about this method is it is easily decentralized, which saves money in transport as well as CO2 production. This would also reduce the needed support infrastructure necessary to create it and distribute it.


D - Xylose
“Pour Some Xylose on Me!”


Xylose Home Run, Almost

Previously, eleven enzymes were combined together to produce H2 almost as efficiently as Percival’s method but it required the use of an expensive substrate so it is not economically feasible when scaled to the size required to be a vehicle energy solution.  By adding phosphate ions, Percival Zhang was able to release near the perfect theoretical amounts of Hydrogen without the added costs.  That is nearly 12 moles of H2 directly from cellulosic and starch avoiding the use of the costly glucose-6 phosphate method of the previously output matching method.

Percival’s Xylose Miracle

To maximize the production of H2 from Xylose, Percival designed a vitro synthetic pathway in which xylose transformed with a result that one mole of Xylose plus six moles of water can generate 10 moles of H2 and 5 moles of carbon dioxide at a cost of one ATP to ADP and phosphate.

Here is the equation:

Xylose to H2 and CO2 Equation
“Pour Some Xylose on Me!”



You might be wondering why they were not able to just use the bacteria to produce the same effect as the enzymes derived from the bacteria.  That is because heat is required during the reaction that would kill the bacteria if it is produced efficiently.  This called an endothermic reaction because heat is absorbed. It is “endon” which means “within” and “thermic” meaning hot.  Literally from the Greek, it means “within hot”.

To test the design they put the enzymes and the raw plant material in a bioreactor at a temperature of 50 degrees Celsius.

Sure enough, after twenty hours the theoretical maximum output of H2 was produced!

They decided to try and avoid the use of ATP to produce H2 by using polyphosphate so they mixed the 13 enzymes with Xylose and Polyphosphate and low and behold, after 20 hours in the bioreactor had passed, they were at a 90% yield of H2. They then threw in a little more polyphosphate after the 21st hour and their yield increased to over 96%!

In the words of Archimedes, “Eureka!”

In their previous work the verified that nearly theoretical yields of CO2 from cellulose by a synthetic pathway, now for a second home run in a row they showed that Xylose can be converted to H2 by a synthetic pathway.

Their process has several advantages over using organisms, including the high output of H2. It also works relatively quickly. It is easy to engineer and control. It is tolerant of toxic elements that are likely to make it into the process. Lastly, it gets rid of the cost generating road blocks that previous methods had.

Xylose Miracle, Yes, BUT…

And as if that wasn’t enough, they also have a solution to the storage problem of Hydrogen.

To give you a little background Hydrogen likes to escape from whatever container you put it in, and it goes boom in its free state. This is a problem of course because no one wants to drive a car that blows up when you hit the rear bumper!

To say the least, it’s a way to ruin your day!

Their solution is to store Hydrogen in the production of carbohydrates.  In a reaction similar to the way your body uses carbohydrates, their method would use a fuel cell that is 99% efficient at producing hydrogen and carbon dioxide! In this form, H2 becomes stable and remains so until the enzymes are added which causes the release of the H2 and CO2.

Remember the CO2 that is produced is contained in the original plant matter when it’s growing. This process does release it to the atmosphere but it’s reabsorbed by the plants next time you grow them for the next batch of cars on the road!

The technology has the ability to produce 2.5 Kilowatt hours of electricity from every kilogram of Carbohydrates. This meets the U.S. Department of Energy’s ultimate solution target.

This technology was licensed to Mascoma, Optafuel/Biomethodes, and Gate Fuels along with six patents. This will generate a 1 Trillion dollar industry over the next 10 years.

Expect this technology to transform the fuel that we use quickly. It will become ubiquitous in no time!


“Pour Some Xylose on Me!”, References

Take a look at “Prompt” here at