The enzymatic route

Despite the potential advantages of enzymatic processing in manufacturing oleochemicals, the process has not yet broken through into mainstream production.

Chemical processing is the wellestablished route for oleochemical production globally and has proven its technical and economic feasibility on a large scale.

However, the main drawback of chemical processing is its high energy consumption. The temperature of esterification/transesterification reactions, for example, ranges from 180-200°C. Such high temperatures darken the intermediate products and produce many unwanted by-products, so that many downstream treatment process steps are needed. Due to this, chemical technology has a high capital investment cost compared to an enzymatic-based plant.

Enzymatic technology uses a mild temperature of about 60°C and allows a selective mechanism, which reduces the need for downstream process steps. As a result, the capital investment cost is lower.

However, an existing manufacturer who already has a well-established conventional chemical process that works highly efficiently may not wish to convert existing conventional units. Working with enzymes requires special equipment and a different industrial set-up. Enzymatic Enzymatic technology offers a ‘green’ route to producing oleochemicals, with several companies already utilising the technology or on the verge of demonstration-scale production Ahmad Mustafa

technology is therefore more attractive for new start-ups at the design and decision stage as the plant-based process costs about two-and-half times less than the chemical route.

Another challenge associated with enzymatic production is the high cost of commercial enzymes and their deactivation if not treated correctly. The enzymatic process would be more profitable if the operational stability of enzymes is maintained for as long as possible. A minimum of two tonnes of product per 1kg of enzyme would maintain process profitability.

However, even with improved enzyme operational stability, the cost of enzymes can never compare favourably with the cost of a chemical catalyst such as sodium hydroxide. The enzymatic process manufacturing cost will always be higher than the chemical process. Consequently, the higher manufacturing cost of the final product is reflected in the final product price.

The question that needs to be asked is: are customers ready to pay a premium for a ‘green’ product?

Green credentials

Recently, manufacturers have started publicising their utilisation of enzymatic technology to market their products.

One such company is Evonik Industries, the first global manufacturer of biotechnologically-produced emollient esters. The company has been making myristyl myristate, decyl cocoate, cetyl ricinoleate and isocetyl palmitate using bioprocess enzymatic technology since 2008.

Evonik emphasises the effectiveness and profitability of using this green technology in practical large-scale applications. These products are highly priced with high profit margins, meaning the cost of enzymes do not negatively affect profits.

In addition, Evonik has dealt with the challenge of the high cost of enzymes by using a fixed-bed reactor with a circulation loop, through which the reaction charge u

Cost parameter

ISBL OSBL Direct capital investment cost (ISBL + OSBL) Engineering cost Contingency cost Fixed capital cost Start-up expenses Working capital Total capital investment

Cost of chemical based plant (US$)

4,626,000 1,387,800 6,013,800

601,380 6,615,180 601,380 902,070 11,041,337

Cost of enzymaticbased plant (US$)

1,786,140 535,842 2,321,982

348,297 2,670,279 232,198 348,297 4,421,054

Table 1: Summary of total capital investment (4,950 tonnes/year capacity)

Source: Ahmad Mustafa

u is pumped long enough to reach the intended yield.

Oleo Misr for Oleochemicals

Another company entering the enzymatic field is Oleo Misr for Oleochemicals, located in Egypt, which plans to be the first firm in the Middle East and Africa to produce esters using enzymatic technology.

The company – working with Novozymes A/S; Egypt’s October University for Modern Sciences and Arts, MSA University; and Nutrivet Misr Company, Egypt – plans to produce nonantibiotic feed additives from palm kernel oil, based on enzymatic technology.

Apart from the lower reaction temperature offered by using lipase as a biocatalyst, the yield of monolaurin obtained was significantly higher compared with using conventional technology. This highlights the selective mechanism of using lipases to catalyse the esterification reaction between lauric acid and glycerol.

The developed blends produced by Oleo Misr comprise mainly monolaurin, with three versions developed as additives for fish, poultry and calf feed.

The three monolaurin-based products are being evaluated through several ongoing trials with Egyptian farms, with promising results being collected. In addition, an agreement was signed between Oleo Misr, Nutrivet and MSA University in January to further strengthen the cooperation in feed animal additives production.

In another research project, Oleo Misr successfully produced glyceryl monostearate on a lab scale using enzymatic technology in a twostep reaction. After many process optimisations, the developed enzymatic technology yielded almost pure monoglycerides with traces of diglycerides

Evonik uses enzymatic technology to produce emollient esters such as myristyl myristate, decyl cocoate, cetyl ricinoleate and isocetyl palmitate Photo: Adobe Stock

and no triglycerides.

Oleo Misr calculated the total investment cost of monoglycerides production using enzymatic technology and chemical technology, with glyceryl monostearate selected as a studying model. The study was performed by calculating the inside battery limits (ISBL) cost, outside battery limits cost (OSBL), engineering cost, contingency cost, startup cost and working capital cost (see Table 1, above).

The enzymatic-based plant has a total investment cost two-and-a-half times lower than the chemical-based plant. This is mainly due to the potential removal of the expensive short path distiller used in chemical technology.

From lab to demo scale

Leading oleochemical producer Oleon is also aiming to move from lab to industrial demonstration scale in enzymatic technology.

Oleon – together with Belgian research organisation VITO and six other European partners from Belgium, France, Germany and Italy – was granted EU Horizon 2020 research funding of €13.3M over four years (September 2019-August 2023).

Their INCITE (Innovative Chemoenzymatic InTEgrated processes) project aims to widen implementation of enzymatic process technologies in the commodity, fine and speciality chemical industry in Europe.

The end goal will be to have an industrial demonstration unit running on enzymatic catalysis at Oleon’s site in Oelegem, near Antwerp.

Oleon has successfully produced isopropyl palmitate enzymatically through a 150kg pilot plant at its production site via lipase-based solvent-free synthesis of oleochemical esters.

Oleon also studied the oils and fats splitting process using enzymatic technology in another project funded by the EU Horizon 2020 programme.

This LIPES project (Life Integrated Process for Enzymatic Splitting of triglycerides) is dedicated to developing an alternative green route to the existing traditional splitting method of triglycerides to fatty acids and glycerin.

Oleon said in its published progress report that using this approach would make the process far more resourceefficient, saving at least 45% water and 80% energy over current approaches. In addition, the new approach will enzymatically produce selected commercially important fatty acids at an overall lower variable cost than existing processes and showcase their use as intermediates in broader applications.

Conclusion

With such ongoing projects based on enzymatic processes and with new start-ups globally, enzymatic technology may begin to replace some existing traditional chemical plants in the near future. Enzymatic technology can replace chemical technology if the operational stability of enzymes is improved. Companies that wish to succeed in this area should therefore have a qualified team of researchers and developers behind them. ●

Ahmad Mustafa is an assistant professor at MSA University in Cairo and a consultant for Oleo Misr for Oleochemicals, Egypt