There is a lot of discussion about bokashi, EM (Effective Microorganisms) and Eco-enzyme. When I read the material on these it seems as if there is a lot of overlap between these three topics and at times they even seem to be the same thing. I thought it would be useful to clarify what they are and differentiate between them.
Eco-enzyme are even available as commercial products in Asia.
What is Bokashi Composting?
I found this definition: “Bokashi composting is a safe, convenient, and quick way to compost food waste in your kitchen, garage, or apartment.”
To get started you need a special bokashi bucket that has a tight lid, and a spigot at the bottom to drain off liquids (pictured below). These will run you $60 to $150, or you can make a DIY for $20. You also need the ‘special sauce’! This is normally a bran, or rice containing Effective Microbes as well as some molasses. Its purpose is to add the microbes and sugar to get the process going.
The process is fairly simple. Put your food scraps in the pail and sprinkle some bokashi bran on top. Squish it down tight to get the air out. Close the lid. Each time you have more scraps, add them to the pail, add bran, and squish. After a few days, liquid starts to form in the bottom of the pail. This needs to be drained or it will start to stink. This liquid, the ‘bokashi leachate (tea)’ can be used to fertilize your indoor and garden plants.
After a few weeks, when the pail is full, you take the contents (the bokashi ferment) outside, and either dig it into your garden, or add it to your compost pile.
It is called a composting process, but it’s not composting. The kitchen scraps go through a fermentation process not unlike the one used to make sauerkraut. This converts various sugars to organic acids like lactic acid and acetic acid.
Composting starts when the bokashi ferment is added to soil.
It is important to note that bokashi is also used in agriculture, which uses large piles of manure and plant waste, along with added microbes. In some parts of Asia the EM are replaced with indigenous microorganisms (IMOs). The IMO’s tend to be home made by mixing cooked rice with soil and sugar, to encourage the growth of microbes. It is clear from both agricultural reports and research that a special EM mixture is not a requirement to carry out bokashi. In fact some people just add yeast.
A study compared different ways of preparing bokashi with different microbes and found they all produced about the same results.
What are Effective Microbes (EM)?
A simple definition is that Effective Microorganisms (EM) are mixed cultures of beneficial naturally-occurring organisms.
The term was coined by Teruo Higa, from Japan, to describe a mixture of approximately 80 different microorganisms that were capable of positively influencing the decomposition of organic matter. This led to the formation of EMRO (EM Research Organization), a company that makes and promotes the use of a variety of EM products. Their main product is EM-1, a general mixture of microbes that can be used for a variety of applications.
‘EM Bokashi’ is fermented rice bran or wheat bran inoculated with EM-1 and is used for bokashi composting.
‘EM Compost’ is fermented organic matter inoculated with EM-1 and is used as a starter in traditional composting.
The actual content of EM-1 is a trade secret but it does contain the following along with other microorganisms.
- Lactic acid bacteria (LAB): Lactobacillus casei
- Photosynthetic bacteria (purple non-sulfur bacteria or PNSB): Rhodopseudomonas palustris
- Yeast: Saccharomyces cerevisiae
A number of other companies now supply an “EM” mixture and there is a lot of information online for making your own concoctions.
What are Eco-enzyme (Garbage Enzymes)?
Garbage enzymes and eco-enzyme are the same thing and are produced from the fermentation of organic waste. A few sources now call this ‘bio-enzyme’.
It is fairly easy to prepare. Take 1 part brown sugar or molasses, 3 parts organic matter (kitchen scraps) and 10 parts water. Some prefer to use mostly fruit peels. Place this in a closed bottle and let sit for 3 months. Open the lid once a week to allow excess pressure to be released. At the end of the process, pour off the liquid – the eco-enzyme. The remaining kitchen scraps can be used just like bokashi ferment.
The liquid eco-enzyme can be used as a cleaner or added to plants as a fertilizer. How good is that – shine your leaves and feed the plant at the same time. Warning – the concentrated form might harm leaves. The produced liquid is usually diluted 1:100 or even 1:1,000 before being used on plants or soil.
It is claimed that the benefits of eco-enzyme are due mostly to the enzymes produced during the fermentation process. It is also fairly acidic.
What are Enzymes?
Enzymes are special proteins made in all living organisms and they carry out most of the chemical reactions that take place in cells. Enzymes build the molecules needed to make cells and they break molecules apart during the decomposition process.
Bacteria don’t have mouths although some can encapsulate small pieces of organic matter. Most get their food by excreting enzymes around themselves. The enzymes digest the organic matter, including other living microbes, that are around them. Once the digested molecules are small enough the bacteria can absorb them through their membranes (skin).
Enzymes are just molecules – they are not living. When added to soil, they will help decompose organic matter and through that process they do provide nutrients for plants.
Bokashi vs Eco-enzyme
These processes are fairly similar. They both ferment kitchen scraps. They both produce organic acids in an anaerobic environment. Both lactic acid bacteria and yeast are involved. In bokashi extra microbes are added while eco-enzyme relies on the natural population found on food scraps. Both methods add a sugar source to get the process started.
Bokashi is a drier process, although the food scraps do contain water. They both produce a solid component and a liquid component. The liquid component in both cases is used as a fertilizer for plants. The solid component is further composted either in a traditional compost pile or by adding it to soil.
The main claimed benefits for bokashi is based in the presence of microbes while eco-enzyme is more about the enzymes. Keep in mind that the microbes in bokashi produce enzymes – so is the end product really that different?
Bokashi and Eco-enzyme Solids
The solids in both cases are very similar. They still look much like the kitchen scraps that were used to start the process. They are clearly not fully decomposed. The material in bokashi may be a bit less fermented, because it is done over a shorter period (2 weeks vs 3 months) and it is done dry.
It is not clear to me how much of the original nutritional value is left in the ferment, but I suspect that most of it remains in the solids since their cell structure is still intact.
Composting this material will add nutrients to soil, will benefit plants and will help improve soil structure. However, this would also be true if the original food scraps were simply buried in the soil, or composted and then buried. The Bokashi and eco-enzyme processes may speed up decomposition, but I can’t find any scientific proof that is actually true.
Bokashi and Eco-enzyme Liquids
Bokashi leachate (tea) has been studied and found to contain various organic acids including lactic and acetic, alcohols, various bacteria and yeast as well as plant nutrients. The following table compares the nutrient levels at full concentration, a diluted form (middle column) which is 2% of the concentrate (1:50 dilution) and normal fertilizer values (MSU fertilizer which is used for growing a wide range of plants including orchids).
Nitrogen levels in Bokashi tea are very low. Phosphorus and potassium are on the high side and the level of several micronutrients are also very low. Bokashi tea also had high levels of sodium (1200 mg/l) and chloride (4300 mg/l). Canned and cooked kitchen scraps will have higher levels than fresh material. Once diluted to the 2% level used in the above table, the leachate will have a sodium value of 24, with 50 being toxic to plants. The chloride is at 85 mg/l and a value of 70 is considered toxic.
Discussions about bokashi tea rarely mention enzymes, but they will also be present.
Much less work has been done to analyze eco-enzyme tea (liquid). It also contains lactic and acetic acids, alcohols, various bacteria and yeast. It contains enzymes including protease, amylase and lipase. It clearly also includes plant nutrients, but I could not find a detailed analysis.
The fermentation for eco-enzyme is normally carried out for 3 months compared to a couple of weeks for bokashi. However the microbe addition in bokashi is higher, so it might be more effective at fermenting the garbage. There is no clear data to show which is better for plants, but I suspect that the differences are more dependent on the starting material, than the actual process.
I have had a detailed look at the claimed benefits for bokashi here. I’ll just discuss the main ones here.
Addition of Microbes
This is one of the main claims for bokashi but can also be made for eco-enzyme. The reality is that the microbes used in both processes are common in the environment. Adding more to soil is not likely to add any benefit, given the fact that soil is always saturated with microbes. There are some studies that show a benefit from the microbes, but most show no positive results.
This is not a surprise to anyone who has followed the studies on compost tea. Adding microbes to soil has no benefits, except in a few very special cases of disease.
Users of bokashi claim that adding the microbes to soil is a benefit and then turn around and say that using the tea to inoculate the next batch of bokashi won’t work – you have to start with fresh EM. The microbes are either there or they are not.
Addition of Enzymes
Many of the claims, especially for eco-enzyme, are based on the addition of enzymes to soil. It is true that enzymes produced by microbes do decompose organic matter which helps feed plants. It is also true that adding enzymes to soil will also have this effect. The problem is that the amount added is so minuscule compared to the volume of soil, that it will have no measurable effect on plant growth.
It also has to be remembered that microbes produce enzymes that degrade proteins (i.e. enzymes), so any enzymes added to soil will not last long. I have reviewed the value of enzymes in soil in Compost Adds Enzymes and Hormones. They don’t add a lot of value to soil or plants.
There are many strange claims for these enzymes.
- Because they (enzymes) are natural and free from chemicals, eco enzymes are easily broken down and harmless to humans and the environment. They are chemicals! If they are easily broken down, which is true, how can they also be so beneficial for plants?
- The enzymes increase the amount of nitrogen. They can’t do that. They can convert one form of nitrogen to another. They could make nitrogen plant available, but they can’t increase the amount of nitrogen.
Addition of Plant Nutrients
Both the teas and the solids contain plant nutrients. When added to soil, they increase the nutrients available to plants and the organic matter in them will help improve soil structure. The same is true for regular compost, or just dropping organic matter on the ground. Going through the gyrations of these processes does not increase the amount of nutrients.
Are Effective Microorganisms Needed?
People performing home bokashi have been conditioned to believe bokashi won’t work without EM-1. In agriculture, bokashi is sometimes made with EM, but a lot of the time it is made with other local microbe concoctions as well as indigenous microorganisms. One study found no difference between using IMO, yeast or nothing. Some people also make their own bokashi bran using IMO that they collect and grow themselves. Others use competing products to EM-1 that contain different organisms. ” Dr. Higa has always stressed that it isn’t the exact combination or ratio of microorganisms that makes EM so powerful, it is the fact that the microbes are working together as a group”.
Fermentation in eco-enzyme happens without the addition of any extra microbes.
One study looked at the effects of different amounts of EM, different amounts of carbohydrates and different temperatures. They found that “acid production (amount of fermentation) was dependent on glucose concentration but not on the amount of EM used.”
There seems to be a lot of hype and promotion of EM-1, but the data seems to indicate that they are not needed for either bokashi or eco-enzyme.
Are Sugar and Molasses the Key?
If you look at the details for carrying out these two processes you will note that both add a form of sugar (brown sugar or molasses). Sugar is a food source for most microbes and it is easy for them to use. It causes a microbe population explosion which in turn produces a lot of CO2 and organic acids. This starts the anaerobic fermentation process.
This process also happens using just the billions and billions of microbes already on the kitchen scraps. Additional microbes are not needed since the existing ones are supercharged with the sugar.
I suspect adding additional microbes, EM or yeast, is a kind of insurance policy to make sure the right kind are there in larger amounts, but that they are not really needed. The added sugar source is more important.
Bokashi vs Eco-enzyme
On a molecular basis, the two methods seem to be almost identical. One is done in water and the other is done dry. I suspect that once we understand these methods better, we will conclude that they are slight variations of the same method.
There are two things that are not clear.
What is more valuable to plants and soil – the tea or the solids? I suspect it is the solids.
How quickly does the solid material decompose? When added to soil it does become unrecognizable in a few weeks and many think it is completely composted, but is that really true? Decomposition is a slow process and our human eyes are poor tools for measuring the degree of decomposition.
This post contains affiliate links to Amazon. Use them to buy anything from Amazon and Garden Myths gets a small commission without any cost to you. Thanks.