By Dr Sunil E Fernando

The natural rubber tree converts a greenhouse gas to a hydrocarbon. It is also capable of delivering it in commercially viable quantities almost on a daily basis, unlike any other. In addition, it retains some carbohydrates produced over a 30-year period, as medium density hardwood. This natural process of the biosynthesis of two products not only sustains the farmer, but also reduces the impact on global warming to some extent due to carbon dioxide extraction. Thus, preserving existing rubber plantations and cultivating more, especially in marginal lands, will help to mitigate an imbalance created due to the production of excessive quantities of a greenhouse gas

Benefits of Growing Rubber: Hevea brasiliensis or the rubber tree began its epic journey in 1875, when Sir Henry Wickham brought 70,000 seeds from Rio Tapajos in the upper Amazon to Kew gardens in London. Of these, 1911 seedlings were planted in Gampaha botanical gardens, Sri Lanka, initiating an agricultural revolution in South East Asia and an industrial revolution globally. Apart from giving 14 million tons of Natural Rubber (NR) consumed annually worldwide, the tree has other attributes listed below.

 Extracting 24.9 kilograms of Carbon dioxide (CO2) Greenhouse gas (GHG) to produce one Kilogram of latex

 Yielding 2.1 cubic meters/tree of wood from GHG as biomass, every 30-year cycle

 Produce easily biodegradable litter, compared to monocultures like Teak

 Require less chemical fertilisers, water and pesticides

 Retains biodiversity as a tropical plant and co-exists with other species allowing for intercropping

The uniqueness of the rubber tree is its ability to fix CO2 almost instantaneously into a hydrocarbon on a daily basis, with water and energy from sunlight while nature took millions of years converting biomass to a hydrocarbon, Petroleum. The tree is a natural solar panel trapping energy from the Sun, propagating a chemical reaction giving a hydrocarbon, while releasing Oxygen to the atmosphere and accumulating a timber resource. Tapped from year 5, the tree removes a GHG every other day, unlike any other plant species, for 11 months of the year for 25 years.

Why Excess CO2 is bad

CO2 present in the atmosphere is a double-edged sword. "CO2-Earth" reports, its concentration increased from 330 ppm in 1975 to 408.55 in September 2019, and further to 410.27 in November 2019. CO2 absorbs Infrared radiation (heat radiation) from the Sun through molecular vibrations, and emit this energy unlike gases like Nitrogen and Oxygen. Ozone, Methane and Nitrous Oxide are other GHG's, which absorb energy from the sun and similarly emit heat, warming the atmosphere.

However, GHG's maintains atmospheric temperatures without converting Earth into an ice ball. Nevertheless, high concentration of GHG in atmosphere, emit more heat to sustain global warming due to an imbalance created by excessive human activity like burning fuel, rearing of cattle/sheep, giving-off excessive CO2 and Methane, respectively. Two confirmed methods to lower ill effects of GHG are, produce less and increase plant cover.

CO2 is the raw materials for all forms of Carbohydrates, Proteins and Fats produced by plants providing for growth and energy in life forms. What is alarming is the excess CO2 produced, accumulating in the atmosphere, and in Oceans. Dissolved CO2 in seawater, raises temperature and forms Carbonic acid, increasing Ocean acidification. Ocean acidification reduces the ability of sea creatures to fix Calcium as Calcium Carbonate, another form of Carbon sink.

Carbon Dioxide Accumulation Antoine Lavoisier said, in a chemical reaction matter is neither created nor destroyed. Producing GHG through human intervention, new matter is not created but it leads to an unsustainable imbalance of matter in the environment. This is what causes the problem.

Figure 1. Figure 1. Representation of the CO2 Cycle (https://serc.carleton.edu/eslabs/carbon/2a.html)

CO2 is a GHG not only produced by burning fuels and biomass. Humans exhale One Kilogram of it daily. Increase in population does not increase CO2, as exhaled balances out by inhaling. But when human population went up from 1 billion 200 years ago to 7 billion now, increase in human activity led to an imbalance in the atmosphere and the Oceans due to release of CO2 and Methane. Biomass generation too is dwindling due to the population pressure. Thus, this imbalance of accumulating matter capable of absorbing heat is the main reason for global warming.

Biosynthesis of Natural Rubber About 2000 plant species produce NR, but Hevea brasiliensis produce commercially exploitable dispersion in water as latex. The biological reason for NR production is not clear, but it may prevent pathogenic microorganisms entering the tree. Latex is found in horizontally arranged interconnected cells called laticifer, in the bark of the tree, High yielding plantations with about 400 trees per hectare have reported a production of 2500 Kg/NR /Year. The theoretical yield potential is estimated at, 7,000 to 10,000 kg/Ha/Year. A tree giving 15 to 30g of rubber per day, tapping on alternative days yields 2.2-4.5 Kg of NR per year. According to Apollo Vredestein R and D, on average 1.9 Kg of NR goes into a tire and a tree produces enough rubber to make 2 tires per year or 50 in lifetime.

Plants take in CO2 for survival. Some converts part into an edible form, as carbohydrate and fats while the rest is converted to forms like cellulose. These may end up as wood, becoming a Carbon sink for a length of time. In rubber trees, the process extends converting part of CO2 to a rubber hydrocarbon containing Carbon and Hydrogen, more akin to Petroleum. This wonder tree makes a hydrocarbon in few minutes, while nature took millions of years to convert biomass derived from CO2 to Petroleum.

The biosynthetic pathway for NR in Hevea begins with the monomer precursor, Isopentenyl pyrophosphate (IPP). IPP is an adduct of Pyrophosphoric acid and Isoprene monomer. However, IPP is not an uncommon material, limited to Hevea, but is formed from carbohydrates, in other plants, algae, bacteria, in mammals and humans. The formation of IPP is said to occur by following two pathways; Mevalonate (MVA) or non-mevalonate (non-MVA), deoxy-xylulose pathway. In rubber trees, breakdown products from carbohydrates like Pyruvates and Glyceraldehydes are transformed into IPP, in Cytosol in Cytoplasm/Plastids in plant cells, in several stages in the presence of many enzymes like mevalonate kinase (MVK) and mevalonate diphosphate decarboxylase (MVD). Figure 2.

Figure 2 Representation of the Formation of IPP through MVA and Non-MVA Pathways (Chiang. C. C. K, 2013, PhD Thesis, the Graduate Faculty of the University of Akron).

On isomerisation with enzyme, Isomerase IPP is converted to Dimethyl allyl pyrophosphate (DMPP). IPP and DMPP are building blocks for diverse groups of bio-molecules like Cholesterol, Vitamin K, Coenzyme Q10 (CoQ10) and Cis-polyisoprene (NR). Figure 3

Figure 3 Pathway to NR Biosynthesis

In rubber producing Russian dandelion (Taraxacum koksaghyz Rodin), enzyme transformation of sugars enrich NR formation. In the summer months, dandelions produce excess sugars and store it as Inulin. The possibility of metabolic engineering assisted enzyme degradation of Inulin to enhance production of IPP and then to NR has been explored for dandelion. Meanwhile Researchers have succeeded in decoding the Genome sequence in Hevea. This can lead to high yielding rubber clones, by locating genes responsible for biosynthesis of rubber.

Latex with 30% NR and 5% non-rubbers is produced in special cells called laticifers located horizontally and a lateral cut of the bark exposes most number, giving latex. Since the laticifer density is genotype dependant determining latex yield, it can give the direction for biologists as a selection marker for high yielding clones. In older rubber trees chemicals inducing Ethylene formation in the bark-tissue or generated it in situ like 2-Chloroethylphosphonic acid, are used as yield stimulants. Such developments, together with appropriate nutrition infusion, can increase NR yields, making rubber cultivation attractive to farmers.

Chloroethylphosphonic acid

Hevea brasiliensis is a dual-purpose tree, making Carbon sinks from CO2 in two ways, as a hydrocarbon and as wood, extracted in a 30-year cycle. Plants like wheat and rice also fix CO2 to give edible Carbohydrates, often twice a year. Nevertheless, human/animal consumption of edible carbohydrates quickly gives CO2 back to the environment. Thus with respect to environmental benefits, producing NR by growing rubber trees is a more favourable option. Fortunately, rubber cultivation has increased from 9.9 in 1975 to 14.0 million hectares in 2018 giving these benefits worldwide.

Preserving and enhancing rubber cultivation

The rubber farmer does a silent service by extracting latex and thus removing substantial quantity of GHG on a daily basis. As NR based products stay longer in service, Carbon in it remains intact for a longer period without burdening the environment. Each tree has the uncanny ability to function as a tap, working 150 days a year to clean up the environment unlike other plant-based options. It leaves a raw material as timber derived from GHG, extracted in every 30-year cycle giving 50 Kg of wood/tree. The global potential for wood at a replanting rate of 3% of acreage annually is, approx 7.30 Mn Tons/ year.

The environmental benefits can be maximised if the farmer taps the tree every other day for 11 months of the year if their livelihood is secularly safeguarded. Going into alternatives for from existing land is counterproductive to the environment. The negative process will occur only if the farmer finds the daily sustenance by growing rubber becomes a hard task. To encourage the farmer, requires a collective and a concerted effort from:

 Buyers giving stable/reasonable price

 Biologists developing fast growing, high yielding, drought and disease resistant trees

 Cultivation experts developing new and less-laborious extraction techniques and attractive intercropping practices

 Technologists adding value to existing NR products and developing new products

• Chemists by modification to give new elastomeric materials from NR as raw materials for other processes

• Environmentalists by increasing international awareness of the benefits of growing rubber

With respect to increased appreciation of the capability of modified NR forms, an enterprising tire manufacturer uses Epoxidised NR/Silica combination in automobile tire treads, to give higher wet grip and low rolling resistance tires. Such greener tires used in hybrid and electric cars, made these vehicles more environmental friendly. Olefinic elastomers like NR, contains reactive double bonds with potential to be modified as raw materials in many applications. Table 1, Figures 4 and 5. Such developments will give impetus to the sustainability and growth of an industry, benefitting the rubber farmer while fixing more GHG as well.

 

 

 

 

 

 

 

 

 

 

ENDS

References:

1. Bhowmik. I (2006), Tripura Rubber Mission Technical Bulletin 2. https://www.co2.earth/

3. Rao. P. S, et.al (1998), Agricultural and Forest Meteorology 3, 90

4. Chiang. C. C. K (2013), Natural rubber biosynthesis, PhD Thesis, The Graduate Faculty of The University of Akron, USA 5. Decoding the rubber tree genome, https://www.sciencedaily.com/releases/2016/06/160624100225.htm

 

 

Dr Sunil E Fernando is Former Executive Director, DPL Group, Sri Lanka, Managing Director Dipped Products (Thailand) Limited, Former Director, DPL Plantations and Kelani Valley Plantations Limited, Sri Lanka, and a Consultant - Latex Products

Ecolomondo Corporation, a leading Canadian innovator in sustainable scrap tyre recycling technology, has announced that its new milling line at Hawkesbury facility has achieved a major milestone during recent testing by reaching a throughput of approximately 2,700 lbs per hour of recovered carbon black (rCB). This result surpasses the company’s projected target of 2,200 lbs per hour.

When the new milling line is completely operational, it should be able to process 2,200 pounds of rCB per hour and provide a particle size distribution of 96 percent between 10 and 15 microns. It is anticipated that the plant would process more than 1.5 million scrap tyres annually, recovering 1,350 MT of process gas while producing 4,500 MT of recovered carbon black, 5,400 MT of oil and 2,250 MT of steel.

The company expects the commercial production of rCB to start by the end of May 2025. After being contacted, offtake clients told the company that they were eagerly expecting a larger supply of steel, oil and rCB, said the company. Depending on end-product market pricing, the company's yearly income from the sale of these sustainable goods plus tipping fees of USD 145 per metric tonne is expected to reach USD 12.1 million, with an estimated EBITDA of 45 to 50 percent, added the company statement.

Jean-François Labbé, Interim CEO, Ecolomondo Corporation, said, “This is a major achievement that brings the Hawkesbury facility closer to full production and commercialisation.”

Global speciality chemicals company Orion S.A. has launched a new bio-circular carbon black called ECOLAR 50 POWDER to provide coatings manufacturers with a new solution for more sustainable coatings.

ECOLAR 50 POWDER, which is entirely based on bio-circular feedstock, has coloristic qualities that are on par with those of ordinary speciality carbon blacks and includes 100 percent biogenic raw material according to 14C analysis. The coloristic qualities of ECOLAR 50 POWDER, a low to medium colour furnace black, offer moderate tinting strength and medium jetness in mass tone applications. ECOLAR 50 POWDER offers equivalent coloristic performance for full-tone and tinting applications, as well as comparable wetting and dispersion characteristics to conventionally manufactured low-colour furnace blacks.

ECOLAR 50 POWDER outperformed other common specialist carbon blacks in achieving medium jetness in a solvent-borne alkyd/melamine stoving enamel system. It created a similar neutral undertone as well. When tested in a water-borne 1K PU coating system, ECOLAR 50 POWDER created a more neutral undertone and jetness that was on par with other regular speciality carbon blacks.

Tilo Lindner, Vice President Global Marketing – Speciality Carbon Black, Orion, said, “We’re leading the way in advancing carbon black to meet increasing industry demands for sustainable products. ECOLAR 50 POWDER enables coatings formulators to develop truly sustainable products in all kinds of coatings applications.”

LD Carbon has inaugurated Korea’s first and largest waste tyre pyrolysis plant in Dangjin, South Korea.

Located in the Dangjin Hapdeok General Industrial Complex, the plant is expected to begin full-scale operation next month. The plant is spread over 29,800 square metres and features two factory buildings and five silos. The plant has an annual capacity to process 50 kilotonnes per annum (ktpa) of tyre chips derived from end-of-life tyres (ELTs).

At the location, LD Carbon uses a two-step pyrolysis process, first turning ELTs into solid char and pyrolysis oil. After that, the business uses a secondary pyrolysis process to further compress the char and create recovered carbon black (rCB). It is anticipated that the Dangjin facility would generate 20 ktpa of rCB and 24 ktpa of pyrolysis oil, which is a substantial increase above the combined output of 7 ktpa at its current pilot plant in Gimcheon. When compared to traditional carbon black, the rCB generated by the technique is said to lower carbon emissions by up to 32 ktpa.

The company is planning to build plants overseas and intends to join the Asian market soon. It has also struck a 10-year offtake deal with SK Incheon Petrochem for its pyrolysis oil.

Speciality chemicals company LANXESS India organised its first exclusive Solutions Day event in Mumbai today to showcase its diversified and sustainable product portfolio to customers and other key stakeholders.

The event was organised to promote the idea of ‘One LANXESS’, where its business units – namely Advanced Industrial Intermediates, Flavors & Fragrances, Inorganic Pigments, Liquid Purification Technologies, Lubricant Additives Business, Material Protection Products, Polymer Additives, Rhein Chemie and Saltigo – displayed their distinctive products and solutions at the event. It provided an opportunity to highlight the cross-business synergies that characterise LANXESS' integrated approach and to present the company's cutting-edge solutions designed for a variety of industrial applications.

Three main business sectors, namely Advanced Industrial Intermediates, Speciality Additives and Consumer Protection Products, are currently the emphasis of LANXESS's strategy shift from a polymers to speciality chemicals company. In order to improve the value provided to clients, the event sought to promote cooperation and creativity across these various business divisions. In order to promote knowledge exchange, discover possible areas for collaboration and capitalise on the capabilities of each business unit to propel overall development and success, the day included interactive workshops, technical presentations and networking opportunities.

Namitesh Roy Choudhury, Vice Chairman & Managing Director, LANXESS India, said “Our goal with Solutions Day is to strengthen our existing partnerships and explore future collaborations that support sustainable industry growth. Through this event, we want to highlight LANXESS’ integrated offerings to all our stakeholders and address the global industrial challenges through the combined power of sustainable chemistry, innovation and responsible business.”