Edible straws made by bacteria are better than paper or plastic ones

The internet is flooded with stories of people who are trying to make better alternatives to paper, plastic and even animal food. They claim that they can be used as a replacement for other resources such as wood, water or animals. To my surprise, few of these replacements actually deliver on their promises. I’m not going to get into the difference between plants and trees, but rather how some of these substitutes may be useful, however bad they taste. This post will show that the bacteria cells from all the straws you buy and eat do come in pretty good shape if used as a substitute for paper and other toxic materials, so don’t start thinking about making this stuff from scratch.

In terms of the science behind straws I recommend using those which are made by a type of bacterium called Streptococcus thermophilus.

This bacterium makes it very easy to take a straw in your home (it does require an expensive set up) from any given stand, through either a leafed kitchen plant or vegetable garden, to the end product. All that is required is a few minutes of work in a lab. There are also lots of options from which you can find them at most major supermarkets.

The first straw that comes to mind when we think about alternatives to plastics is perhaps this one. It is made by S. thermophilus and is sold in the USA and Canada for $29.99, but elsewhere for anything in the range of $9-15. The straw itself gets a great deal of attention because it is produced out of a variety of kinds of corn starch. A number of scientists have said they expect the straw to provide over 70% less greenhouse gas emissions than standard cardboard. In addition, the straw does reduce the amount of energy required to treat and make a straw which reduces our overall carbon footprint (though that may not be what is being cited). You can read more about the latest developments in straw technologies here.

I am sure most governments here in the US are already considering similar technologies, especially after having had excellent success using natural rubber over the last few years to replace PVC pipes and various types of pipe insulation (see here, for example). Some governments have moved toward banning the use of synthetic fibres while others are moving toward banning single-use plastics like gloves and bags in public spaces (see here). Regardless, the straw industry does seem poised to flourish if something is done.

I mentioned earlier that the straw actually comes in fairly good shape if used as a substitute for other toxins like paper, plastic or animal food. But why would anyone want to produce their own version? If there is a way to make a straw without much effort, why wouldn’t that technology come into play in the case of synthetic alternatives to plastics?

But let’s explore what this straw might actually look like.

The straw used in the picture (the right hand side) was initially made by using an organism known as Bacillus subtilis. Much of the straw now found in grocery stores around the world is made by this same bacterium. Its original name came from two different kinds of straw: one made with a special kind of wheat straw that is thinner and less flexible and another with a thicker, less flexible straw. The former is still made primarily from wheat straw (though some straws are grown from soy) and are relatively inexpensive to make. However, the latter is generally considered a “living straw” and uses a yeast cell as an enzyme to turn sugars into ethanol. These enzymes are what gives the straw its amazing breathable qualities, so this is where the term living straw comes from.

The whole structure of the straw could be seen in the image below. As noted by Nick Shabana, who in his article published in Scientific American this year said,

“One big advantage of using yeast as a renewable fuel source is that ethanol from barley or soy can be extracted in large quantities and easily blended into alcohol, to produce ethanol from sugar cane (the second half of the image shows the straw being prepared using that method),” he wrote. “But the main advantage of bacilli (the main organism behind cornstarch and its many cousins) as a sustainable resource for producing renewable fuels is that enzymes that convert cornstarch and its kinase proteins into ethanol, or sugar, are everywhere in nature. So, bacilli are well suited to produce ethanol from the simple sugars in cornstarch and related carbohydrate enzymes,” he wrote.

The images above show the ethanol production capacity of bacilli (in blue), cornstarch (red), cornstarch (in green), glucose and other small sugars produced by the microbes. Cornstarch can be converted into ethanol by certain enzymes (the image below shows two separate procedures), glucose can be used to make ethanol by fermentation (top right) and sugars such as honey (bottom left) have various functions (bulk of image shown). We saw just above that cornstarch has several active forms (the three distinct ones are named in Roman numerals) which allow it to be turned into multiple species of ethanol-producing organisms. One would expect that the ethanol produced would be available in large amounts. While ethanol production requires an enormous amount of energy, it also produces enough electricity to offset at least 6 times that would have been generated by burning fossil fuels. Even so, ethanol production needs water to be free of organic matter so we don’t need to worry about running out of freshwater.

As part of his argument in favor of using cornstarch, Nick Shabana reported that “cornstarch can be used to make ethanol by fermenting cornstarch to produce the ethanol molecule, which can then be combined with glucose to produce ethanol. With enough cornstarch, ethanol can serve as a transportation fuel, or as a co-oligomer with fats to form biodiesel, according to current research. He continued to note, however, that ethanol also undergoes chemical changes to give it a pleasant flavor (see cornstarch as a biofuels producer). That could be used to make “taste straws”, says Shabana. His explanation is intriguing, but I’m sure it won’t go down well.

I’ll leave it up to Mr. Shabana to decide whether his arguments are valid or not. Personally, I am in favour of his ideas, but I do think it would be wise for us to wait and see if things move into more complicated ways of using cornstarch to produce ethanol.

Showing cornstarch as a viable alternative to straws made from animal parts of straws is not surprising at all and it does have a long history to back it up. After the late nineteenth century, cornstarch was used in some industries as a replacement media for animal parts of straws (and straws as a replacement medium for other wastes such as coal ash, sand and various types of industrial waste matter). Around 1840’s cornstarch became increasingly popular due to the increasing popularity of corn as a staple ingredient for baked goods, and gradually it became used in other sectors too. It has been speculated that cornstarch could be used as a replacement for oil from hemp seeds. More recently, it found its way into non-food applications as in building material for concrete and steelmaking (including concrete cement and steel, respectively). And so far it seems to be proving itself more than anything else.

In the early 1970’s cornstarch was a commodity used widely throughout Europe, North America, Australia and Hawaii. Today it is more commonly used for other industrial purposes and in countries as diverse as Russia, Argentina and Germany to name a few.

Cornstarch has numerous advantages over straws made of animal parts. For starters, cornstarch is biodegradable and produces much lower levels of greenhouse gases (by far greater than straws made from animal parts). What’s more, cornstarch works as a primary raw material (which is fine if that means you are not going to eat it). Also cornstarch has a huge potential to be used as a renewable fuel which, given the choice, I think is a pretty compelling proposition. Cornstarch can then be turned into ethanol (and ethanol is itself a renewable fuel) by fermentation. Finally, cornstarch has a wonderful array of biological activity. Research has shown cornstarch can produce many important enzymes and thus provide ample opportunities for developing new technologies that produce both cornstarch and ethanol.

Cornstarch is also incredibly resilient. When exposed to stress, cornstarch undergoes stress treatments, causing cornstarch to grow taller, and bigger. This makes cornstarch relatively safer to consume as opposed to straws that may only grow smaller and less resilient if damaged. The cornstarch growing process can also be scaled down significantly. Another benefit is that cornstarch (and hence cornstarch) grows quickly. An experiment has indicated that cornstarch can be cultivated at rates comparable to corn plants on a farm and so can be harvested at much closer distances.