Carrageenan extracted from red seaweeds could be used as an antifungal

A recent study, published in the Journal of Applied Phycology, assessed if carrageenan could be used as an antifungal.

Carrageenan is a sugar extracted from some red seaweeds that is commonly used in a variety of food products as a thickening agent. A previous post went into great detail about carrageenan traits, uses, and impact on human health.

The recent study examined kappa/iota carrageenan belonging to the gametophyte phase and a hybrid xi/theta carrageenan in the tetrasporophyte phase of Chondracanthus teedei  applied to a few species in the genus Alternaria. Alternaria species are known as major plant pathogens. They are also common allergens in humans, growing indoors and causing hay fever or hypersensitivity reactions that sometimes lead to asthma.

Carrageenan induced the formation of swollen hyphal segments upon exposure to as little as 125 and 60 μg mL−1. These results are similar as to those induced by antifungals targeting the fungal cell wall.

The researchers concluded that carrageenan from Chondracanthus teedei  causes physical alterations of the cell wall in Alternaria sp. indicating antifungal activity.

New report: "Development of Offshore Seaweed Cultivation: food safety, cultivation, ecology and economy"

Offshore of northern Europe, a seaweed farm known as NSF (North Sea Farm). NSF was established in 2014 and is committed to developing a strong and healthy seaweed supply chain, in and from the Netherlands. This farm has been studied in a number of ways to assess ecological and economical impacts.

A recent report was just released evaluating economics, food safety, and ecological impacts of offshore seaweed farming.

Studies like these are extremely valuable to validate ecosystem services provided by seaweed farming, and should be conducted in numerous locations around the USA to be ecosystem specific.

General conclusions from the report below

• high variability in chemical and contaminant composition of kelps, with only one month between sampling moments, was observed. This demonstrates the potential to harvest at the right moment, to provide the processing industry with desired products. However, it simultaneously shows the challenge to provide products with stable biochemical composition.

• economic analysis indicates that relatively low-value markets such as the alginates are within reach for seaweed production in the North Sea, though for the near future a mix of medium- and low-value markets needs to be targeted

• seaweed cultivation can have significant effect on the surrounding ecosystem, including biodiversity enhancement. But site specific information is required for the North Sea to evaluate how this activity relates to for example requirements by marine framework directives, and if farm management can further stimulate the ecosystem services provided by seaweed cultivation (through timing of harvest and/or technical adaptations to become more nature inclusive).

Seaweed Farmers in Japan are Creating new Varieties to Deal with Climate Change.

Undaria pinnatifida  (wakame) is a seaweed extensively cultivated, and is one of the most valuable edible seaweeds in Japan, Korea, and China. The cultivation season usually starts from autumn and runs through to spring, where the seaweed is grown on long lines suspended in the ocean.

However, the cultivation period has been delayed due to rising temperatures caused by global climate change. This prompted many germlings (juvenile sporophytes) of U. pinnatifida to fall from the strings during nursery cultivation. In response, seaweed farmers are creating new verities of seaweed, similarly to how a traditional land based farmer would cross pollinate varieties of fruits and vegetables. (For more information on the process read this article)

In a recent paper, researches crossed two varieties of U. pinnatifida to create a heat tolerant variety called NW-1. They then grew NW-1 along side with the standard variety HGU-1. The result was more juveniles remained attached to the long line and had more growth/ individual.

As oceans continue to heat, seaweed breading programs could help seaweed biomass and biodiversity loss due to climate change.

Brown Seaweeds Could be Used to Make Bioethanol

Bioethanol fuel is mainly produced by the sugar fermentation process, although it can also be manufactured by the chemical process of reacting ethylene with steam. The main sources of sugar required to produce ethanol come from fuel or energy crops. These crops are grown specifically for energy use and include corn, maize and wheat crops, waste straw, willow and popular trees, sawdust, reed canary grass, cord grasses, jerusalem artichoke, myscanthus and sorghum plants.

Recent research has turned to macroalgae as a potential source of sugars. The most abundant sugars in brown algae are alginate, mannitol, and glucan; whereby the degradation of these polysaccharides requires specific enzymes for the release of monosaccharides. Monosaccharides are most efficiently fermented into ethanol by Saccharomyces cerevisiae and Escherichia coli strains of bacteria.

Using brown seaweeds as a source of bioethanol could reduce pressure on food crops, and help draw down CO2 from the oceans. While biofuels still release CO2, they reduce the demand for finite fuel resources.

Here is a link to a chapter in Advances in Feedstock Conversion Technologies for Alternative Fuels and Bioproducts that outlines the process.

100 year old maps help create historic digital kelp distribution

There are concerns that the global distribution of kelp is dwindling due to climate change, pollution, or over grazing. However, incomplete records of kelp distribution and density make it hard to evaluate the actual kelp loss.

University of Victoria geography Prof. Maycira Costa was introduced to a collection of historical British nautical charts. Dr. Costa quickly realized that kelp distribution was noted on some of these charts.

Using those British admiralty charts from 1858 to 1956, Costa and her research team have now created the first historical digital map of B.C.'s coastal kelp forests. Now they will be able to compare the historical maps with the satellite images from 2002 until 2017 to better understand how much kelp has been lost.

Read the full article here

κ-Carrageenan Hydrogel as a Coating Material for Fertilizers

A recent study published in the Journal of Polymers and the Environment evaluated using k-Carrageenan as a coating for fertilizer granules.

The study focused on addressing one of the biggest problems facing the worlds waterways: nutrification from agriculture runoff. Carrageenan, which is natural sugar from some red seaweeds, was tested as a time release coating for NPK (Nitrogen, Phosphorus, and Potassium) fertilizer grains.

The results showed a 12-18% reduction in NPK loss to water washing without negatively effecting plant growth. The researchers argue this to be viable way to reduce amount of fertilizer applied to cops and the amount of nutrients washed into surrounding environments.

The Study can be viewed here

Umami- What it is and how you get it from seaweed

You may have come across the word umami, it’s commonplace in Japanese restaurants and on packaged foods such as ramen or seaweed. Umami can be described as a pleasant "brothy" or "meaty" taste with a long-lasting, mouthwatering and coating sensation over the tongue.

Umami, is a loan word from the Japanese  (うま味), umami can be translated as "pleasant savory taste." The word was first proposed in 1908 by Kikunae Ikeda. It wasn’t until 1985 the term was recognized as a scientific term to describe the taste of glutamates and nucleotides at the first Umami International Symposium in Hawaii. This symposium is still active today.

The English synonym would be Savory

Seaweeds are known to produce Umami flavor and are commonly used to make broths. A recent article published in the Journal of Food Measurement and Characterization outlined ideal flavor extraction process for Laminaria japonica, and showed all the flavor components. Below is a breakdown of the chemical constituents of the Umami taste in Laminaria japonica.

“Electronic tongue and electronic nose were used to assess the taste and flavor of the hydrolysate, respectively. Hexanal (43.31 ± 0.57%), (E)-2-octenal (10.42 ± 0.34%), nonanal (6.91 ± 0.65%), pentanal (6.41 ± 0.97%), heptanal (4.64 ± 0.26) and 4-ethylcyclohexanol (4.52 ± 0.21%) were the most abundant flavor compounds in the enzymatic hydrolysate with % peak areas in GC–MS. The contents of aspartic acid (11.27 ± 1.12%) and glutamic acid (13.79 ± 0.21%) were higher than other free amino acids in the enzymatic hydrolysate. Electronic tongue revealed a taste profile characterized by high scores on umami and saltiness .”

The shellfish industry needs a kelping hand in fighting ocean acidification

Ocean acidification is a daunting problem for shellfish farmers. It turns out that when the water becomes more acidic, the organisms aren’t so good at building their shells or reproducing. Oyster farms off the coast of Washington have already started to see the detrimental effects of increasing acidity.

In response, Paul G. Allen awarded $1.5 million to the Puget Sound Restoration Fund to investigate how kelp could help. Kelp and other seaweeds are able to take up CO2 out of the water, and therefore would make a micro climate of less acidic water. The research being led by Dr. Jonathan Davis , is specifically aimed at how kelps could be used around shellfish farms to create a acid buffer.

Davis is so optimistic, he has already began researching how the seaweed can be used as an additional commercial product for shellfish farmers. He is actively exploring kelp uses from food to fuel.

This multi-culture approach is really good idea. First off, these seaweeds would contribute to carbon drawdown, aiding in the removal of CO2 in the oceans. Additional benefits are protecting a farmers shellfish product while also adding a new revenue stream by selling seaweed products.

You can read more about the project here

You can read an article about Dr. Davis here

Extracting proteins from seaweed just got a little easier.

If you were to talk into your local GNC vitamin shop, you would quickly realize that there is a wide range of options for protein supplementation. Depending on your price range, dietary restrictions, and ethics, you can choose from a variety of protein sources: milk, soy, pea, egg, hemp, rice, and other plants.

Why don’t we see seaweed protein? Seaweeds are fast growing, rich in protein, and are highly sustainable. A recent publication in the Journal of Applied Phycology suggests that their complex polysaccharide matrix hinders protein extraction. Reported conventional methods for seaweed protein extraction include aqueous, acidic and alkaline methods where extraction yield varies from 24 to 59%. The study focused on using enzymes to enhance the extraction process and was able to extract 74% of the proteins from giant kelp (M. pyrifera)

These results establish a firm basis for further studies on seaweed protein extracts as potential functional ingredients, or towards the production of bioactive peptides through a straightforward, and environmentally sustainable methodology.

Shrimp farming is getting a boost from incorporating seaweeds

Aquaculture is beginning to shift from mono-culture to integrated multi-trophic aquaculture (IMTA). While IMTA is still relativity a new idea in the industry, nature has been doing it all along and new studies keep illustrating the benefits.

A study just came out this month (Jan 2019) that looked into adding seaweed to shrimp farms. The study added three seaweeds: Gracilaria vermiculophylla, Ulva lactuca,  and Dictyota dichotoma to ponds growing white legged shrimp Litopenaeus vannamei. Then shrimp were infected with V. parahaemolyticus and WSSV to assess disease resistance and response.

The use of macroalgae in co-culture with L. vannamei provided a nutritional benefit that achieved higher growth than the control organisms, as well as improvements of the ammonium concentration and immune response after infection with V. parahaemolyticus and WSSV.

The study concluded that these additional benefits were diet related, however, live seaweeds would change the water properties and testing water quality would be an interesting next step.

This is a good example how a company could change from one product to two while enhancing yield and quality of the original product with very little additional cost.

This research was published in the Journal of Fish & Shellfish Immunology

How ocean acidification could restructure natural seaweed communities

Sean Connell, of the Environment Institute at the University of Adelaide, recently conducted a study on the effects of ocean acidification (OA) on seaweed communities.

The study was completed in New Zealand’s Bay of Plenty where volcanic vents raise CO2 and increase the water acidity. What the researchers found was that kelp domination was replaced by fast growing turf species. Not only did the volcanic vents increase the growth of turf species, but also inhibited the production of a primary grazer (urchins). These coupled effects allowed turf species to become the dominant in simulated future ocean conditions.

The upper graph showing the control plot where kelp becomes the dominant. The lower graph shows plots with elevated CO2 that become turf dominated.

Predictive studies are full of ambiguity, and fail to address longer term trends such as geographical shifts and adaptions, however, knowing these case studies allows us to be mindful of what we might expect along our own coast.

This study was published in Ecology and can be viewed here

Sodium alginate and human stem cells used to 3D-print tissues

Researchers at Penn State University found sodium alginate from seaweed can be used to “print” human tissues. Alginate mixed with human stem cells can be 3D-printed into tiny particles that create breathable tissues.

Currently the technology is limited to small strands, however, the researchers are confidant they will be able to create larger tissue patches in the future. The researchers believe these tissues could be used for bone and cartilage surgery , such as knee restoration, cartilage defects, and osteoarthritis.

Read the article here

New study uses matrix approach to evaluate ecosystem services by seaweeds

A new study recently came out from the Department of Conservation, Wellington, New Zealand, that uses a matrix approach to evaluate ecosystem services provided by a number of marine species.

The list of species evaluated included seaweeds, crustaceans, worms, and more. The services provided were broken into three main categories: habitat & supporting services , regulating services, and provisioning services.

While this study was New Zealand focused, it serves as a good reference of positive impacts by a species. Furthermore, a number of the study species are currently farmed and this study could be useful in aquaculture spatial planning.

The paper can be viewed here

Carrageenan and silver to combat drug resistant bacteria

Carrageenan is a sugar within some red seaweeds that gets a lot of attention in relation to human health and food additives. We covered this topic thoroughly here.

Lately carrageenan has been making headlines as a sustained release matrix for health applications. Researchers at Indian Institute of Technology, Roorkee (IIT-Roorkee), found that they could stabilize and extend the short shelf life of silver nanoparticles by adding a carrageenan matrix. The nano composite was able to kill both Gram-positive and Gram-negative bacteria, and had a shelf life of 6 months. The researchers believe this technology will be useful for wound dressing, food packing, and plan to investigate the possibilities as an anti-fungal and anti-viral agent as well.

The published research can be found here

Read more about the project from the Tech Explorist here

Climate change is raising iodine levels in seaweed. Cause for alarm? We think not.

A recent publication in Global Change Biology, reported that changing atmospheric and oceanic conditions, due to climate change, are raising the levels of iodine in seaweeds that can transfer up the food web. We think this is a great paper, and we strongly believe that many aspects of the ocean should be analysed to model future ocean conditions. Most work on algae in respects to climate change have been limited to calcifying reds, and the coral symbiot zooxanthellae. Seaweeds are the second largest biomass harvested from the oceans and more research is needed for that market.

A few news articles ran with the idea that seaweeds are becoming toxic, and are making headlines. While humans need iodine, too much can cause some of the same symptoms as iodine deficiency, including goiter (an enlarged thyroid gland) (NIH). However, we suggest caution when saying all seaweeds will become toxic.

For instance in the paper the study species Saccharina japonica was used, which is a species that is known to already have high concentrations of iodine. Saccharina and other species of brown seaweeds (kelp/ kombu) have much higher concentrations of iodine than other species (see figure below). Most consumed seaweeds (dulse, nori, wakame) have iodine levels 5x lower than Saccharina, and even with increases from climate change would not be considered dangerous.

People around the world choose to eat seaweeds because it’s rich in minerals including iodine, and we suspect this fact will not change. We encourage people to pay attention to the nutrition labeling on seaweed foods and monitor how much they consume. When reading papers or nutrition labels, note the seaweed condition (Dry vs. fresh). Most weight in seaweeds is attributed to water, and a serving size between dry and fresh can be a large difference. We also want to emphasize that iodine is not accumulated in your tissues, such as heavy metals.

We hope good studies like this continue, but use caution when reading news that oversimplifies the results.

Image from American Thyroid Association 2004. Full article here

Seaweed common names: Kombu

There are many names for commonly consumed seaweeds. However, the species they refer to vary by region and culture. We will cover some of the most commonly used names for seaweeds, and review the differences between connotation and denotation. This series will review some of the most common common-names in use.

Previous posts include: Nori, Wakame, Laver

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Kombu is a common name for seaweeds that typically belong to the group of brown seaweeds: Laminariaceae. Kombu is traditionally used for soup stocks, salads, and even fertilizer. Brown seaweeds are high in minerals and by adding them dishes one can improve the nutritional value of their food.

The word kombu is Japanese, but it’s thought to be borrowed from the Chinese. In old Japanese the word for seaweed was “me” as in “waka-me”. The predominant theory, is that kombu is derived from the Chinese word 昆布 kūnbù, which is traced back to the 3rd century in China. However, records from the 8th century are spotty at best in their descriptions of kūnbù, and it is impossible to know what species of seaweeds they were referring to.

Nowadays there are modifiers to separate the different species of kombu. (Borrowed from Wikipedia).

• Saccharina japonica (Laminaria japonica), Ma-kombu [ja] –

• Saccharina japonica var. religiosa (Laminaria religiosa), Hosome-kombu [ja] –

• Saccharina japonica var. diabolica (Laminaria diabolica), Oni-kombu [ja] –

• Saccharina japonica var. ochotensis (Laminaria ochotensis), Rishiri-kombu [ja] – commonly used for soup stocks

• Saccharina latissima (Laminaria saccharina), Karafuto-kombu – It contains mannitol and is considered sweeter.

• Saccharina angustata (Laminaria angustata), Mitsuishi-kombu [ja] – commonly used in the making of dashi

• Saccharina longissima (Laminaria longissima),　Naga-kombu [ja] –

• Saccharina coriacea (Laminaria coriacea), Gaggara-kombu [ja] –

• Saccharina sculpera (Kjellmaniella sculpera), Gagome-kombu [ja] –

• Saccharina longipedalis (Laminaria longipedalis), Enaga-kombu –

• Saccharina gyrata (Kjellmaniella gyrata), tororo-kombu [ja] –

• Saccharina cichorioides (Laminaria cichorioides), Chijimi-kombu –

• Arthrothamnus bifidus, nekoashi-kombu [ja] –

However, in other parts of the world the term kombu is used to describe other species of brown algae such as Saccharina or Laminaria. For example, the company Salt Point Seaweed calls Laminaria setchellii, California kombu.

Seaweed smart material stronger than steel

Researchers at Brown University discovered a way to make a new smart material mixing alginate with graphene oxide. The new material can be 3D printed and is stronger than steel. Read more about this new amazing material here.

Closing the nutrient loop with seaweed farming.

As discussed in the last post, agriculture runoff is a huge problem. Nutrients are running off the land and into our oceans.Today in a recent article from Scientific America, the idea was batted around to take up ocean nutrients with kelp then turn it into fertilizers. These fertilizers could then be used again on land to replenish the nutrients lost. Not only would this help close the nutrient loop, but also take excess carbon out of the oceans.

This is just another example how seaweeds can help reverse negative anthropogenic impacts to our oceans.

Seaweeds can facilitate symbiotic microbes in agriculture

Modern agriculture is a marvel of the 21st century. Crop production has surpassed our expectations, many times over, in the last 100 years. However, this production has come with a cost. What is now being called our nitrogen addiction, refers to the amount of fertilizers used on farmland. The traditional soaking of soil is inefficient and leads to runoff: where nutrients are leaked into other surrounding ecosystems or the waterways.

Doesn’t sound so bad, what the problem with extra nutrients in the water? Well, the added nutrients cause boom bust cycles of other plants and algae that can tip the balance of an ecosystem. Currently there are numerous microalgae blooms off the coast of the USA, all are said to be a factor of agriculture runoff. This has caused an outcry for more responsible farming practices in reducing their nutrient loading.

One group in the UK has started using algae extracts and microbes to help crop efficiency. They claim that the seaweed extract facilitates microbes that help crops take up more water and nutrients, and therefore can reduce the amount of farm input by 20%. By reducing the amount of water and fertilizer used, the runoff will be far less than without the seaweed’s help. This could end up being a key strategy for responsible farming practices.