By James Oldcorn, Freelance Writer

Published 17th July, 2022

Extreme habitats such as hydrothermal vents or hypersaline lakes contain microorganisms that have adapted over time to survive their intense environmental conditions. As such, these microbes demonstrate an extreme environmental resilience that can be harnessed for greener, more sustainable industrial biotechnology.

So, what constitutes an extreme environment? They are dynamic habitats that are considered inhospitable to most life. While most occur naturally, such as geothermal springs, glaciers, brine pools etc. These environments can also be anthropogenic, such as oil spills and mining wastelands. As can be expected, these environments are subject to intense conditions such as high temperatures, pHs or salinities, to name a few.

However, these areas are not completely devoid of life, and as the famous Dr Ian Malcolm once stated ‘life finds a way.’ These environments are a testament to that. Aptly named the extremophiles, the wealth of resilient microorganisms found in these environments have evolved their physiology over millennia to survive extreme conditions that most other organisms cannot tolerate. And with that, so have their enzymes or ‘extremozymes’.

Enzymes, typically described as biological machines, are named as such for their huge role in breaking down and/or building up most organic reactions. They increase the rate of these reactions significantly and without them, life would otherwise be impossible.

The economic importance of enzymes cannot be overstated, with an estimated value of $5.8 billion USD in 2020, and predicted annual growth of 6.8%. Industrial enzymes are exciting biotechnology used in many important and contemporary processes, such as paper making, detergents, and food manufacturing. They also show great promise in future environmental applications, including biofuel production and oil/plastic degradation.

Enzymes from non-extreme environments are utilised for their ease of access (such as E. coli), but since their resilience is governed by their host environments, enzymes found in extreme environments are better suited for industrial biotech applications.

‘So, what constitutes an extreme environment? They are dynamic habitats that are considered inhospitable to most life.’

One proposed solution is to upgrade our current industrial enzymes to more industrially tolerant enzymes known as ‘extremozymes.’ These enzymes were discovered in extreme environments, and in doing so improved the industries’ environmental impact.

Let’s start with the case of detergents: Enzymes can be used as a biodegradable, eco-friendly alternative to common cleaning detergents, however, most washing machines still use too much energy. Novozyme, a global biotech company located in Bagsværd, outside of Copenhagen, recently discovered a fungal enzyme derived from an arctic environment which significantly lowered the heat requirement, and therefore energy consumption, for the detergent to wash.

Another big environmental issue facing modern industrial biotechnologies such as biofuel production is the overreliance and excessive consumption of fresh water. Fresh water removal has extractive ramifications on the environment and desalination is an expensive and energy-intensive process.

While a solution to this may come in the form of utilising marine water, typical industrial enzymes cannot act in extreme salt conditions. However, as can be guessed, extreme hypersaline environments potentially hold the key to unlocking this solution.

Extremozymes with high salt tolerance have the potential to revolutionise industrial biotechnology in an environmentally friendly capacity. Saline extremozymes could provide a competitive advantage against their chemical rivals as freshwater use is a huge bottleneck for many industrial processes. Many salt-tolerant enzymes have recently been discovered in extreme environments such as hypersaline lakes and anthropogenic salterns, hopefully leading to a revolution in industrial salt-water consumption.

Extremozymes may also help us with addressing important environmental calamities, such as the aforementioned oil spills and plastic degradation. In environments where plastic deposits are common, scientists are constantly discovering new microorganisms that display exciting plastic-degrading capabilities via novel enzymes.

The potential for plastic/oil-degrading enzymes may prove to be revolutionary for environmental sustainability, potentially providing an eco-friendly solution to plastics and oil clean-up processes.

Unfortunately, these oil/plastic degrading enzymes are currently unviable and far from a panacea to the problem as degradation is currently too slow and energy intensive. However, the future is bright as increasing the temperature of these reactions has been shown to rapidly increase degradation times. Further exploration into extreme environments for more thermo-stable extremozymes is necessary, as these discovered enzymes do not have the heat capacity to tolerate increased temperatures.

‘The potential for plastic/oil-degrading enzymes may prove to be revolutionary for environmental sustainability.’

Thermostable extremozymes may also have the potential to increase the viability of biofuels. A potentially renewable and sustainable technology, second generation biofuels are an ingenious idea involving the production of sustainable fuel from waste feedstock/biomass, using enzymes to mediate the reaction. However, biofuels are typically unfeasible due to low efficiencies and yield, and as such cannot currently compete with fossil fuels.

However, as seen with plastic degradation, viability may be achievable with a significant increase in reaction temperature, increasing its yield. Finding the right enzymes will be scientists' next step in this process.

Resilient, thermostable biofuel-converting enzymes are being discovered globally, from hot springs in India, oceanic geothermal vents and even Italian volcanoes. The diversity these enzymes show in function and performance is incredibly diverse on a global and local scale, and hopefully, after further development, they can be utilised to make biofuels a competitively viable fuel alternative.

The world is abundant with these extreme environments, and although seemingly hazardous and desolate, they are obscuring enormous treasures that are revolutionising many endeavours.

In a world whose climate is becoming increasingly extreme, learning from the organisms that have inhabited and survived such conditions may provide useful solutions to adapting to the problems induced by our changing climate.

Technological advantages are allowing us to uncover the lucrative secrets of the microscopic domain, and with it, we should gain a greater appreciation of the true biodiversity in the world. Even environments seen as ‘desolate’ can provide a solution to many of our contemporary issues, highlighting the need to preserve all our natural world.

Feature Image: Cristiano Firmani | Unsplash

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