Tag Archives: bacterial nanocellulose

Nanocellulose and food waste, an Australian perspective

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A trio of Australian academics (Alan Labas, Benjamin Matthew Long, and Dylan Liu, all from Federation University Australia) have written a September 26, 2023 essay about nanocellulose derived from food waste for The Conversation, Note: Links have been removed,

Food waste is a global problem with approximately 1.3 billion tonnes of food wasted each year throughout the food lifecycle – from the farm to food manufacturers and households.

Across the food supply chain, Australians waste around 7.6 million tonnes of food each year. This costs our economy approximately A$36.6 billion annually.

In a recent study published in Bioresource Technology Reports, we have found a way to use food waste for making a versatile material known as nanocellulose. In particular, we used acid whey – a significant dairy production waste material that it usually difficult to dispose of.

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For those who may not be familiar with nanocellulose, a lot of research was done here in Canada with a focus on using forest and agricultural waste products to produce nanocellulose. (See the CelluForce and Blue Goose Biorefineries websites for more about nanocellulose production, which in both their cases results in a specific material known as cellulose nanocrystals [CNC].) There’s more about the different kinds of nanocellulose later in this post.

The September 26, 2023 essay offers a good description of nanocellulose,

Nanocellulose is a biopolymer, which means it’s a naturally produced long chain of sugars. It has remarkable properties – bacterial nanocellulose is strong, chemically stable and biocompatible, meaning it’s not harmful to human cells. This makes it a highly marketable product with applications in packaging, wound treatments, drug delivery or food production.

Then, there’s this about the production process, from the September 26, 2023 essay, Note: A link has been removed,

The traditional approach for making nanocellulose can be expensive, uses large amounts of energy and takes a long time. Some types of nanocellulose production [emphasis mine] also use a chemical process that produces unwanted waste byproducts.

By contrast, our new approach uses just food waste and a symbiotic culture of bacteria and yeasts (SCOBY) – something you may be familiar with as a kombucha starter. Our process is low cost, consumes little energy and produces no waste.

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… Lovers of home-brewed kombucha may actually be familiar with the raw nanocellulose material – it forms as a floating off-white structure called a pellicle. Some people already use this kombucha by-product as vegan leather.) A similar pellicle formed on our acid whey mixture.

I’m not sure if the “types of nanocellulose production” the writers are referring to are different types of nanocellose materials or different types of nanocellulose extraction.

A little more about nanocellulose

The Nanocellulose Wikipedia entry highlights the different materials that can be derived from nanocellulose, Note: Links have been removed,

Nanocellulose is a term referring to nano-structured cellulose. This may be either cellulose nanocrystal (CNC or NCC [nanocellulose crystal]), cellulose nanofibers (CNF) also called nanofibrillated cellulose (NFC), or bacterial nanocellulose, which refers to nano-structured cellulose produced by bacteria.

CNF is a material composed of nanosized cellulose fibrils with a high aspect ratio (length to width ratio). Typical fibril widths are 5–20 nanometers with a wide range of lengths, typically several micrometers. It is pseudo-plastic and exhibits thixotropy, the property of certain gels or fluids that are thick (viscous) under normal conditions, but become less viscous when shaken or agitated. When the shearing forces are removed the gel regains much of its original state. The fibrils are isolated from any cellulose containing source including wood-based fibers (pulp fibers) through high-pressure, high temperature and high velocity impact homogenization, grinding or microfluidization (see manufacture below).[1][2][3]

Nanocellulose can also be obtained from native fibers by an acid hydrolysis, giving rise to highly crystalline and rigid nanoparticles which are shorter (100s to 1000 nanometers) than the cellulose nanofibrils (CNF) obtained through homogenization, microfluiodization or grinding routes. The resulting material is known as cellulose nanocrystal (CNC).[4]

Nanochitin is similar in its nanostructure to nanocellulose.

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Interestingly, Canadian development efforts are not mentioned in the essay until the very end, where we are lost in a plethora of other mentions, Note 1: Links have been removed; Note 2: All emphases mine,

A lthough wood-driven nanocellulose was first produced in 1983 by Herrick[7] and Turbak,[6] its commercial production postponed till 2010, mainly due to the high production energy consumption and high production cost. Innventia AB (Sweden) established the first nanocellulose pilot production plant 2010.[109] Companies and research institutes actively producing micro and nano fibrillated cellulose include: American Process (US), Borregaard (Norway), CelluComp (UK), Chuetsu Pulp and Paper (Japan), CTP/FCBA (France), Daicel (Japan), Dai-ichi Kyogo (Japan), Empa (Switzerland), FiberLean Technologies (UK), InoFib (France), Nano Novin Polymer Co. (Iran), Nippon Paper (Japan), Norske Skog (Norway), Oji Paper (Japan), RISE (Sweden), SAPPI (Netherlands), Seiko PMC (Japan), Stora Enso (Finland), Sugino Machine (Japan), Suzano (Brazil), Tianjin Haojia Cellulose Co. Ltd (China), University of Maine (US), UPM (Finland), US Forest Products Lab (US), VTT (Finland), and Weidmann Fiber Technology (Switzerland).[110] Companies and research institutes actively producing cellulose nanocrystals include: Alberta Innovates (Canada), American Process (US), Blue Goose Biorefineries (Canada), CelluForce (Canada), FPInnovations (Canada), Hangzhou Yeuha Technology Co. (China), Melodea (Israel/Sweden), Sweetwater Energy (US), Tianjin Haojia Cellulose Co. Ltd (China), and US Forest Products Lab (US).[110] Companies and research institutes actively producing cellulose filaments include: Kruger (Canada), Performance BioFilaments (Canada), and Tianjin Haojia Cellulose Co. Ltd (China).[110] Cellucomp (Scotland) produces Curran, a root-vegetable based nanocellulose.[111]

This leaves me with a couple of questions: Is my understanding of the nanocellulose story insular or Is the Wikipedia entry a little US-centric? It’s entirely possible the answer to both questions could be yes.

Why so much interest in nanocellulose? Money

From the September 26, 2023 essay, Note: A link has been removed,

Demand for nanocellulose is growing worldwide. The global market was valued at US$0.4 billion in 2022 (A$0.6bn) and is expected to grow to US$2 billion by 2030 (A$3.1bn). Bacterial nanocellulose produced from food waste can help to satisfy this demand.

This growth is in part due to how we can use nanocellulose instead of petroleum-based and other non-renewable materials in things like packaging. Among its desirable properties, nanocellulose is also fully biodegradable.

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If you have time, do read the September 26, 2023 essay in its entirety.

H/t to September 27, 2023 news item on phys.org

Cleaning water with bacteria

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There seems to be much interest in bacteria as collaborators as opposed to the old ‘enemy that must be destoyed’ concept. The latest collaborative effort was announced in a January 19,2019 news item on Nanowerk,

More than one in 10 people in the world lack basic drinking water access, and by 2025, half of the world’s population will be living in water-stressed areas, which is why access to clean water is one of the National Academy of Engineering’s Grand Challenges. Engineers at Washington University in St. Louis [WUSTL] have designed a novel membrane technology that purifies water while preventing biofouling, or buildup of bacteria and other harmful microorganisms that reduce the flow of water.

And they used bacteria to build such filtering membranes.

A January 17, 2019 WUSTL news release by Beth Miller, which originated the news item, provides more detail,

Srikanth Singamaneni, professor of mechanical engineering & materials science, and Young-Shin Jun, professor of energy, environmental & chemical engineering, and their teams blended their expertise to develop an ultrafiltration membrane using graphene oxide and bacterial nanocellulose that they found to be highly efficient, long-lasting and environmentally friendly. If their technique were to be scaled up to a large size, it could benefit many developing countries where clean water is scarce.

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Biofouling accounts for nearly half of all membrane fouling and is highly challenging to eradicate completely. Singamaneni and Jun have been tackling this challenge together for nearly five years. They previously developed other membranes using gold nanostars, but wanted to design one that used less expensive materials.

Their new membrane begins with feeding Gluconacetobacter hansenii bacteria a sugary substance so that they form cellulose nanofibers when in water. The team then incorporated graphene oxide (GO) flakes into the bacterial nanocellulose while it was growing, essentially trapping GO in the membrane to make it stable and durable.

After GO is incorporated, the membrane is treated with base solution to kill Gluconacetobacter. During this process, the oxygen groups of GO are eliminated, making it reduced GO.  When the team shone sunlight onto the membrane, the reduced GO flakes immediately generated heat, which is dissipated into the surrounding water and bacteria nanocellulose.

Ironically, the membrane created from bacteria also can kill bacteria.
“If you want to purify water with microorganisms in it, the reduced graphene oxide in the membrane can absorb the sunlight, heat the membrane and kill the bacteria,” Singamaneni said.

Singamaneni and Jun and their team exposed the membrane to E. coli bacteria, then shone light on the membrane’s surface. After being irradiated with light for just 3 minutes, the E. coli bacteria died. The team determined that the membrane quickly heated to above the 70 degrees Celsius required to deteriorate the cell walls of E. coli bacteria.

While the bacteria are killed, the researchers had a pristine membrane with a high quality of nanocellulose fibers that was able to filter water twice as fast as commercially available ultrafiltration membranes under a high operating pressure.

When they did the same experiment on a membrane made from bacterial nanocellulose without the reduced GO, the E. coli bacteria stayed alive.

“This is like 3-D printing with microorganisms,” Jun said. “We can add whatever we like to the bacteria nanocellulose during its growth. We looked at it under different pH conditions similar to what we encounter in the environment, and these membranes are much more stable compared to membranes prepared by vacuum filtration or spin-coating of graphene oxide.”

While Singamaneni and Jun acknowledge that implementing this process in conventional reverse osmosis systems is taxing, they propose a spiral-wound module system, similar to a roll of towels. It could be equipped with LEDs or a type of nanogenerator that harnesses mechanical energy from the fluid flow to produce light and heat, which would reduce the overall cost.

Here’s a link to and a citation for the paper,

Photothermally Active Reduced Graphene Oxide/Bacterial Nanocellulose Composites as Biofouling-Resistant Ultrafiltration Membranes by Qisheng Jiang, Deoukchen Ghim, Sisi Cao, Sirimuvva Tadepalli, Keng-Ku Liu, Hyuna Kwon, Jingyi Luan, Yujia Min, Young-Shin Jun, and Srikanth Singamaneni. Environ. Sci. Technol., 2019, 53 (1), pp 412–421 DOI: 10.1021/acs.est.8b02772 Publication Date (Web): September 14, print Jan. 2, 2019.

Copyright © 2018 American Chemical Society

This paper is behind a paywall.

Algae factories could produce nanocellulose for biofuels and more

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The American Chemical Society (ACS) is holding its 245th meeting April 7 – 11, 2013 and its first International Symposium on Bacterial Nanocellulose simultaneously. I have written about nanocellulose previously but it’s always been concerned with the type derived from plant matter; bacterial nanocellulose is new to me but not the scientific community as the Apr. 8, 2013 news item on Azonano notes,

In the 1800s, French scientist Louis Pasteur first discovered that vinegar-making [and Kombucha tea and nata de coco] bacteria make “a sort of moist skin, swollen, gelatinous and slippery” — a “skin” now known as bacterial nanocellulose. Nanocellulose made by bacteria has advantages, including ease of production and high purity that fostered the kind of scientific excitement reflected in the first international symposium on the topic, Brown [R. Malcolm Brown, Jr., Ph.D.] pointed out.

Before going on to this latest research, here’s a description of cellulose and nanocellulose as per its presence in plant material (from the news item),

Cellulose is the most abundant organic polymer on Earth, a material, like plastics, consisting of molecules linked together into long chains. Cellulose makes up tree trunks and branches, corn stalks and cotton fibers, and it is the main component of paper and cardboard. People eat cellulose in “dietary fiber,” the indigestible material in fruits and vegetables. Cows, horses and termites can digest the cellulose in grass, hay and wood.

Most cellulose consists of wood fibers and cell wall remains. Very few living organisms can actually synthesize and secrete cellulose in its native nanostructure form of microfibrils. At this level, nanometer-scale fibrils are very hydrophilic and look like jelly. A nanometer is one-millionth the thickness of a U.S. dime. Nevertheless, cellulose shares the unique properties of other nanometer-sized materials — properties much different from large quantities of the same material. Nanocellulose-based materials can be stronger than steel and stiffer than Kevlar. Great strength, light weight and other advantages has fostered interest in using it in everything from lightweight armor and ballistic glass to wound dressings and scaffolds for growing replacement organs for transplantation.

A new kind of bacteria actively entered the nanocellulose picture in 2001 (from the news item) allowing Brown to exploit research he had been pursuing since the 1970s (from the news item),

Brown recalled that in 2001, a discovery by David Nobles, Ph.D., a member of the research team at the University of Texas at Austin, refocused their research on nanocellulose, but with a different microbe. Nobles established that several kinds of blue-green algae, which are mainly photosynthetic bacteria much like the vinegar-making bacteria in basic structure; however, these blue-green algae, or cyanobacteria, as they are called, can produce nanocellulose. One of the largest problems with cyanobacterial nanocellulose is that it is not made in abundant amounts in nature. If it could be scaled up, Brown describes this as “one of the most important discoveries in plant biology.”

While I find the science interesting, it’s Brown’s comments about the policy and politics of commercializing nanocellulose-based fuels that intrigue me (from the news item),

In his report at the ACS meeting, Brown described how his team already has genetically engineered the cyanobacteria to produce one form of nanocellulose, the long-chain, or polymer, form of the material. And they are moving ahead with the next step, engineering the cyanobacteria to synthesize a more complete form of nanocellulose, one that is a polymer with a crystalline architecture. He also said that operations are being scaled up, with research moving from laboratory-sized tests to larger outdoor facilities.

Brown expressly pointed out that one of the major barriers to commercializing nanocellulose fuels involves national policy and politics, rather than science. Biofuels, he said, will face a difficult time for decades into the future in competing with the less-expensive natural gas now available with hydraulic fracturing, or “fracking.”  [emphasis mine] In the long run, the United States will need sustainable biofuels, he said, citing the importance of national energy policies that foster parallel development and commercialization of biofuels.