Indigofera tinctoria

  • 14/08/2002

This dye plant was at the heart of Mahatma Gandhi's first satyagraha against the unfair Tinkathia or British taxation system, practiced on the indigo cultivators in Champaran, Bihar. For the British, India was Indigo and Indigo, India.

The use of indigo, a biennial plant with yellow flowers and blue leaves, dates back centuries, when it was used as medicine to induce nausea and vomiting. The Venetian explorer, Marco Polo passed through India in the 13th century and first reported on the preparations of indigo dye in India. As an important cash crop, the British encouraged the cultivation of indigo as the dye content in its leaves is much higher than any other dye yielding plant. Indians were the masters in the use of this dye.

But with the discovery of synthetic indigo, the export of natural indigo from India fell considerably, from 40,000 tonnes in 1895 to just 1,000 tonnes in 1914. Even the land under indigo cultivation declined from nearly seven lakh hectares in 1896 to 4,500 hectares in 1956. Today, indigo is cultivated in only 2000 hectares in the states of Assam, Andhra Pradesh, West Bengal, Bihar, Tamil Nadu and Pondicherry. Synthetic German indigo is cheaper and the preferred dye.

Scientists are working hard to use biotechnology tools to synthesise indigo in laboratories. A group in Munster, Germany, has identified a genes from a microbe, Ralstonia eutropha and inserted them into the bacterium E coli, which produces indigo. Another group of scientists from Japan isolated a strain of the bacterium Acinetobacter Sp ST-550 from humus soil, fed it with chemical indole and got indigo.

In India three scientists from the Institute of Microbial technology, in Chandigarh, B Bhushan, S K Samanta and Rakesh Jain, engineered strains of the bacterium Psuedomonas putida and E coli with genes that direct the synthesis of indigo. This resulted in five recombinant strains. When fed with indole, each of these produced indigo. All the strains produced indigo in good quantities. Rakesh Jain was given the Nova Nordisk Award for the year 2000 for this work. Sadly, there is no Mahatma to fight for the farmers this time around.

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