Transporting and disposing of waste ethically and cost-effectively is a challenge in many industries, especially with the current heightened emphasis on sustainability, bringing down carbon footprints and boosting green credentials. One surprising new solution for upcycling the by-products of forestry and agricultural processes uses ultrasonic technology to extract cellulose, lignin and sugars for use in other industries. The extraction process itself is zero waste and low energy, and the high-value biochemicals produced have a broad range of applications – from cosmetics to construction – contributing to a circular economy. Dr Andy West, chief chemist at Sonichem, discusses how this groundbreaking approach turns agroforestry by-products into valuable commodities.

POPULATION levels throughout most of human existence have been kept in check by disease, climate fluctuations and other social factors, but advances in medicine, nutrition and technology gave rise to unprecedented expansion in the 20th century.

This advancement is certainly impressive, but it has also placed extraordinary pressure on the natural environment. Demand for precious resources like land, food, water and fossil fuels has increased, and we are now producing waste, pollutants and greenhouse gases at an alarming rate. Linear consumption is reaching its limit and a shift in perspective is needed to meet our present needs and preserve resources for generations to come.

LEAVING THE LINEAR ECONOMY BEHIND

Linear business models based on the concept of ‘take, make and dispose’ have dominated the globe since the beginning of the third industrial revolution. The goal of a linear economy is to produce and sell as many products as possible, without concern for the goods and materials that are disposed of before extracting their maximum value. This approach has been particularly evident in the agricultural and food production sectors, industries that generate and discard non-food biomass in the order of 140 gigatonnes annually, contributing to sustainability issues and disregarding its capacity for valorisation.

At present, practices around the use and management of lignocellulose biomass by-products from farmlands and forests are neither efficient nor universally applied.

Instead, low-value remains – like peanut shells, corn leaves and manure from agriculture, as well as tree stumps, woodchips and sawdust from forestry – are typically left to decay, burned in their natural form, or transformed into wood pellets for incineration at power plants. 

WANT MORE ON BIOMASS?

 

These traditional disposal methods waste a sizeable portion of non-food biomass each year, ignoring its potential to effectively act as starting materials for the production of biochemicals, polymers and building products.

This approach also poses an environmental risk, as decomposing biomass can pollute water sources and contribute to soil erosion. Additionally, the processing, transportation and combustion of wood pellets requires significant energy input and results in greenhouse gas emissions.

MAKING THE MOST OF CIRCULAR VALUE CHAINS

Forestry Journal:

The agriculture and forestry sectors need to embrace new approaches to the recovery and reuse of woody biomass to minimise waste and help preserve the earth’s resources. One groundbreaking solution – developed by the UK company Sonichem – uses a unique biorefinery process to close the biomass production loop, ensuring that lignocellulose is upcycled and preventing large amounts of resources being wasted. This biomass is made up of three components – cellulose, lignin and hemicellulose – which can be separated by a clean, zero-waste ultrasonic fractionation technology to produce valuable bio-based chemicals. 

These biomass-derived chemicals could replace the finite petrochemicals that traditionally appear in many products integral to modern society, including plastics, fertilisers, clothing, digital devices, detergents and medical equipment. For example, microcrystalline cellulose produced through ultrasonic fractionation has an average particle size of about 100 microns, making it ideal for use in food and beverages, cosmetics and performance composites.

Similarly, lignin – the most valuable of the three biochemicals – can be used to replace toxic aromatic petrochemicals, added to industrial composites like cement to improve flow, spun into carbon fibres and incorporated into cosmetic products to add UV protection and antioxidant properties.

Finally, hemicellulose can be extracted as monomeric sugars with potential applications as bio-based surfactants or films, natural dyes, nutraceuticals, pharmaceuticals and even jet fuel. The multiple applications of these products add significant monetary value to agricultural by-products, and Sonichem’s method can convert one tonne of woody biomass worth just £45 into £365 of biochemicals.