Everyone loves stylish leather clothes, shoes and accessories. But industrial leather production is tough on the environment – it uses lots of water and harmful tanning compounds including chromium salts, which together produce very toxic effluent.
Could we replace the harmful compounds altogether? Probably – using a legume called tara that naturally contains large quantities of tannins in its fruit. Powdered tara pods are already being used as an alternative to chromium salts, and Peru, where the tara tree (Caesalpinia spinosa) grows high in the Andes mountains, is the world’s largest exporter of tara.
The trouble is, the vast majority of tara pods are collected from wild forests in different regions of Peru where differing environmental conditions, such rainfall, affect not just the availability of pods but also their tannin content. Leather manufacturers, however, need a consistent supply.
The first step in making tara a standard ingredient in leather tanning is to gather information about the plant from all the regions in which it grows. This is where Henry Bruno Bonilla’s work comes in. Together with colleagues he is assessing molecular markers to analyse genetic diversity among 12 wild populations of tara in the main producing areas of Peru.
So far, Henry and his team have gathered juvenile leaves, and standardized a protocol for extracting DNA from them. “Next,” he explains, “we will amplify and analyse the DNA to establish each plant’s unique fingerprint. That will give us a baseline from which we can start developing strategies to genetically improve tara and develop plants with pods that consistently contain high levels of tannin, or ones that regularly produce a lot of fruit.
“We really have to develop a comprehensive and integrated understanding of tara to ensure its place in the leather industry,” Henry concludes. “Tara is poised to make a huge difference in alleviating environmental pollution, as well as improving the livelihoods of the rural families who collect the pods, and could even cultivate it.”
Henry Bonilla Bruno, a 2013 Bayer Young Environmental Envoy, studies at the National University of San Marcos, Lima, Peru.