Global warming, urban pollution and reserves depletion of fossil fuels have been the driving forces for current research on the use of alternative energy sources, especially those derived from agricultural biomass.

In this sense, ethanol produced from different renewable or organic feedstocks constitutes an alternative fuel for spark ignition engines as well as ethanol processing.

Using ethanol as a fuel decreases fossil fuel consumption and increases energy supply security.

It can be used neat or blended with gasoline. Additionally, it is considered biodegradable and sulphur free.

Its carbon content has agricultural crops as a consequence, when it is released during the combustion process there is no black carbon exposure.

Background

As such scientists in East Africa have been breeding Banana mainly to obtain its fruit  for food consumption but now they are innovating a number of products including its associated residual biomass to obtain products such as banana flour used in confectionery industries, banana stem used to process Ethanol and banana fibre for processing braids among others, including banana lint.

Uganda is known as banana republic with farmers growing a range of banana varieties for food security as well as for export.

However scientists at the National Agricultural Research Laboratories (NaRL) located on the Eastern Part of Kampala in Waksio district where banana research is the main component are now going beyond breeding banana varieties for increased yields and for resistance against pests and diseases by processing industrial products.

The scientists have gone ahead to add value to the East African highland banana (Matoke) where they are processing flour, Bioethanol products from banana stems, hair braids and banana lint  as well as banana starch for pharmaceutical industries including food especially in the confectionary industry.

Ethanol production process

Pan Africa Agriculture Magazine speaking to Yusufu Mukasa a food Chemist at the Food Processing Technology and Incubation centre at NARL in Kawanda, he explained the process of Ethanol production as below.

According to Mukasa, his team of scientists have been working hand in hand with farmers over a period of two years to fulfil the idea of processing ethanol from banana stems.

This is because farmers play a key role in growing the East African highland banana in the various regions in Uganda, namely central and the Western regions where banana is grown most.

Most farmers grow East African Highland banana from locally bred varieties namely Naroban 6H and 7H, M9, Nakitembe and Nakabululu among others.

It is from these banana varieties that the scientist remove the stems to process Ethanol

“These is a scientific process which has been used in countries such as India and other countries in South Eastern Asia where a lot of banana is grown. The process may differ because of the differences in mixing the raw materials,” he noted.

One process is where a primary tool to analyze the ethanol production process from an integrated point of view is offered by exergy analysis.

Ethanol production stages of using Banana stems starts with planting and growing the crop which may require the use of fertilizers, pesticides and fungicide.

The feedstock used to produce ethanol are the banana stems obtained from the roots which is extracted after it is uprooted.

These roots are then transported to the production facility at Narl where they are washed and classified.

“It is then crushed into pieces, left to dry and mixed with Sorghum or millet in drums where it is left to ferment for a period of 6-24 hours depending of the brewing system.  Thereafter ethanol is extracted and packaged for industrial use,” Mukasa notes.

He adds that during the acidification process, hydrolysis diluted Sulfuric acid is used for reducing the pH of the mixture which is shaken and heated by steam up to 100 degrees Celsius.

The mixture is also neutralized and filtered before being prepared for fermentation.

The liquid produced can be marketed as a sweetener or used as a raw material to produce ethanol.

During the fermentation process about 2% of the liquid is used for yeast growing in aerobic conditions.

The remaining liquid is used to produce ethanol. When the yeast is put under anaerobic conditions, its metabolic route is deviated to produce ethanol.

After 6 hours, about 95% of the starch chains are transformed into glucose and the corresponding chemical reaction is presented.

So far the team has done this at research level and they have further gone ahead to refine it for hand washing for prevention of Covid-19.

They have also gone ahead to demonstrate the process with farmers in Kasese district who are engaged in brewing local Alcohol which the farmers says once mixed with sorghum or millet, it can be consumed as alcohol because the spirit level is mild.

The scientists intend to team up with breweries industries in order to produce ethanol in large volumes for commercialisation.

Starch extraction

Apart from processing ethanol, Mukasa and team are also extracting banana starch from its fingers for industrial use.

The team obtains a bunch of East African Highland banana from locally bred varieties namely Naroban 6H and 7H, M9, Nakitembe and Nakabululu among others.

It is then peeled, washed, crushed and dried over a period of time in the oven at the Institute. This is done under a regulated temperature.

Once they obtain the banana powder of a required volume, it is mixed with water and a solution of sodium bisulfite ion, a food preservative.

The liquid suspension of the resulting mixture is then centrifuged to separate the crushed banana finger material and the white banana starch will settle below the backed

According to Mukasa, banana contains small volumes of starch, therefore it requires a bigger volume of peeled banana to obtain the required volume of starch.

He says the main target is to use the starch for blending Pharmaceutical products produced within the country.

Banana fibre processing

Braids

Dr Jimmy Tindamanyire a laboratory manager at the Institute explains that scientists have been working with the private sector players involved in processing braids for hair plaiting way back in 2020.

This is after realising synthetic fibres have their own challenges yet braid processed from banana fibre is soft.

There are already existing industries in Kampala where these banana braids are processed, packaged and sold in a number of marketing outlets.

Banana lint

Another product which the scientists have begun working on is processing banana fibre and refining it into lint for processing clothes.

This research is still at the Laboratory level and it is promising because already they are achieved the white colour they expect just like the colour for cotton lint.

Scientists speak out

Elizabeth Kakhasa a food scientist at the Institute notes that the above innovations have been possible with potential to grow further.

This is because NaRL is known to be the centre for banana breeding not only in Uganda but the entire East Africa.

To be specific, the Institute has the Food Processing Technology and Incubation centre where the necessary food processing machines have been installed.

It is currently teaming up with private sector who have brought on board a number of young scientists interested in carrying out food processors. They are brought on board as incubatees.

Once they acquire the required knowledge, they start their own food processing companies where they are capable of processing, packaging and marketing.