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December 2007

Article

 

Common plant could bring wealth

George Dayimani demonstrates the length of an A. americana leaf 

Associated with liquor beverages similar to tequila, extracted for decades, the spiky Agave americana can become a coveted source of utilisation ranging from paper-making, composites for the automotive industry to the pharmaceutical and food industries.

In a research study with a view to greater utilisation of A. americana, the CSIR found that all parts of A. americana can be utilised successfully for various applications. The 'zero-waste' use of the plant would enable its production and processing to be translated into a viable and sustainable Agave industry in South Africa.

The results of this research formed the basis for developing a general concept for commercialising the A. americana in the rural areas of the Great Karoo.

The Eastern Cape is particularly impoverished, with unemployment of 60% in the Great Karoo alone. Land claims by emerging farmers are currently in progress, but the 5 000 hectare farms to be allocated will not be sufficient for economic independence without some crop cultivation. The climate and soil of the Great Karoo are not favourable for the cultivation of commercial crops.

The only plant of value that grows in the arid Karoo and that can also grow on eroded soil is the A. americana. In the early 1900s, Agave plants were distributed throughout South Africa for erosion control and as a fodder crop in droughts.

 'Batchos' (harvesters) at work in a 'Blue Agave' field. In front, a cut pina

The plant is currently already being used for the production of an alcoholic beverage by fermentation of the heart (pina) of the plant, chiefly for export purposes.

The Agave genus, comprising around 140 species, occurs and is cultivated in arid and semi-arid regions worldwide. This family includes leaf fibre plants, such as Agave americana, Agave sisalana and Agave tequilana. Agave plants are native to Mexico and other parts of the Caribbean region. The best known and most common application of the A. tequilana, also known as Blue Agave, is the production of tequila, an alcoholic beverage, from the sap of the pinas.

In the study done by CSIR Materials Science and Manufacturing, A. americana leaves were randomly harvested in the Graaff-Reinet area and supplied to the CSIR for evaluation.

Tests were carried out with regard to the fibre contained in the plant, particularly fibre extraction and Agave fibre-based paper. Of special interest were fructans and inulin. Fructans are oligo- or polysaccharides that comprise at least two adjacent fructose monomers. Fructans have value in the health and food arenas, and occur in nature in a polydisperse form. Inulin has been successfully tested as a vaccine adjuvant.

From the CSIR study it was clear that A. americana fibre can be utilised for the production of nonwovens. Two main applications were identified namely, geo-textiles and composite materials for the automotive industry.

The pina of the A. americana contains up to 25% of inulin. The leaf base of the local A. americana contains up to 16% of fructans. Both the pina and leaf base can be utilised for the commercial production of long-chain inulin and fructans, which have application as vaccine adjuvants in the pharmaceutical industry and fat substitutes and low calorie sweeteners in the food industry, respectively.

Pina waste and short-fibre textiles are suitable for small scale and commercial paper-making.

The CSIR results could lead to the birth of a new industry in South Africa, transformation of the rural economy and job provision for hundreds of subsistence farmers and entrepreneurs in the struggling Great Karoo.


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  Article and images courtesy CSIR News.

 

 

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