|
Sci Tech
Indigo nation: Champaran to Chandigarh
INDIA'S EXPERTISE in preparing and using vegetable dyes dates back to thousands of years. The Harappans had this technology, as made obvious by the remnants of a dyed fabric, wrapped on a silver vase. Further proof comes form the paintings in the Ajanta Caves, as well as from the writing in Kautilya's Artha Sastra, which refers to dyes and their uses. Ancient Indians knew not only how to make and use dyes but also mordants (which help in holding fast the dyes) and resists (which help to selectively prevent dyes form touching the cloth). Eighth century Central Asia and Egypt knew of Indian textiles. Marco Polo, who passed through India in the13th century, was the first to report on the preparations of Indigo dye in India. Indigo was known to, and used by, ancient Greeks and Romans, as a pigment used in paintings. It is very likely, however, that the name Indigo, attributing its association with India, came after Marco Polo's report.
Indigo has verily held a sustained presence and identity in the history of enterprise, economics and politics of India. The historian Dr.Lotika Varadarajan writes in the book "Indian Leven in Een Kleur" (CIP -GKB; The Hague, Holland, 1985, pp. 65-72) about the antiquity of Indigo dyeing in India, and how its blue colour was thought to be of tamasic quality or character (lowest amongst the three gunas or sensibilities, frame of mind or character - Satvam, Rajas and Tamas) in Hindu symbolism and in Tantrik beliefs. Mrs. Kausalya Santhanam covers the textile printing history of India admirably in the June 20, 1999 issue of Folio, the Sunday magazine of The Hindu, and reminds us of how block printed, resist- dyed textiles from Gujarat and the Deccan adorned Europeans and their homes from the 15th to the 19th centuries. A flourishing trade in textiles and dyes existed between the Golconda kingdom of Telangana and Qutub Shahi, Persia for centuries.
It was thus natural that when the British colonized India, many of them started indigo plantations in Bihar and nearby. The exploitation and cruel maltreatment of native workers by these white planters forms an important part of the saga of India's freedom movement. The British District Collectors either turned a blind eye, or even abetted in such suppressions. The bubble finally burst about 150 years ago. Close on the heels of the "Sepoy Mutiny", the peasant labourers of Bihar revolted against the colonial indigo planters. A remarkable and poignant anti-indigo play Nil Darpan (The Mirror of Indigo) was written and played in parts of Bihar during 1859-62. A Jesuit priest called James Long translated into English, which highlighted how the peasant was exploited. For this act, Mr. Long was put in prison and fined by the colonial judge. But this aroused the conscience of many. Mr. John Beames, a sensitive but outspoken civil servant, was posted around that time as District Officer at Champaran, the home of indigo planters in Bihar and many an act and decision that he took was in favour of the peasant, which evoked the wrath of the planters. (They had him transferred to Orissa. But the irrepressible Beames acted true to his mind here too, and succeeded in removing or rewriting many an unfair rule. Philip Woodruff writes warmly about Beames in his book "The Men who Ruled India"). In a repeat of this some sixty years later, Mahatma Gandhi spoke out about the inhuman treatment of the Champaran Peasants and ignited the nation into a non-violent battle for freedom. Thus Indigo is India and India, Indigo.
Where is the science in all this? It is in the making of the dye from the plant. The plant, a yellow-flowered biennial with bluish leaves, is a cousin of mustard. In Europe, it is the woad plant (Isatis tinctoria to the botanist). The leaves are crushed into a paste, piled up into a stinking compost by adding a variety of unmentionables, including some as hand bran, and fermented for a few days in a vat. Dr. John Edmonds, PhilipJohn and others from the University of Reading, UK, showed about 3 years ago that the fermentation in the vat comes about because of a member of the Clostridium family of bacteria. The ash neutralizes the acid produced during the fermentation while the bran supplies the bug with the complex sugars needed for its growth and happiness. Dr. Edmonds is quoted to marvel: "What's amazing is that at a time when there was no chemistry at all, the dyers kept their woad vats empirically — with the aid of smellmostly — between pH 8.5 and 9". This is the best pH or acidity range for the recovery of indigo; a bit below 8.5 or above 9, the yield drops precipitously.
While the Europeans used woad or Isatis tinctoria, the Indian plant Indigofera tinctoria or Nila, has a higher indigo content and the methodology used by the dyers in India is remarkably similar and efficient. The technology in our country was handed down from fathers to sons over the centuries. In a nation full of castes and communities, each specializing in one art, craft or technology, it was the Kurmis of Bihar and U.P., the Kumbis of Maratha and Deccan, the Niralis of Central India, and certain groups of Muslim dyers who have been exponents of this form of medieval biotechnology.
As chemistry advanced at a rapid pace in the mid-nineteenth century, the chemical identity and molecular structure of the indigo molecule was worked out by Perkin and his associates in England around 1870.
They found it to be 2,2' - biinidolinyliden- 3,3'- dione, and devised an easy method of making it in the chemistry laboratory. Take 4 grams ofortho-nitrobenzaldehyde and 40 ml acetone, add 20 ml of pure water and slowly add 16 ml of a molar solution of NaOH, stir vigorously and let stand for 5 minutes. Filter the solution and recover the solid indigo that is precipitated.
This chemical discovery dealt a deathblow to the flourishing indigo plantations of India. As a result, the excesses by the frustrated planters increased on the poor native who was squeezed to his last drop. This is what led to the Champaran riots, inviting Mahatma Gandhi, adding greater fillip and people's participation in the Independence movement.
The microbiology of indigo production has also been honed finer in recent times, thanks to our greater understanding of genetics and recombinant DNA technology. We get a feel for this when we scan the literature published during the last couple of years. A group in Munster, Germany, has identified a handful of genes from the microbe called Ralstonia eutropha, cut them from there, put them each as a plasmid or a `bangle' and inserted them into the common bacterium E. coli. The engineered coli now produces indigo. Another group from Japan has isolated a strain of the bacterium called Acinetobacter Sp ST-550 from fumus soil,fed it with the chemical indole and has obtained indigo. What these two reports (published in the journal Applied Microbiology and Biotechnology in2001 and 2002) mean is that you can now make indigo not in a field or a farm but in a fermentor or a lab. We have thus moved indigo from the plant to plasmids.
To me, a particularly exciting find was an even earlier paper published in this area by three Indian youngsters — B. Bhushan, S.K.Samanta and Rakesh Jain — all from the CSIR Institute of Microbial Technology at Chandigarh. Reporting in the July 2000 issue of Letters in Applied Microbiology, they have engineered strains of the bacterium Psuedomouas putida (one which degrades naphthalene) and of E. coli, with the relevant genes that direct the synthesis of indigo, and have come out with five recombinant strains.
When fed indole as the starting material inthe nutrient medium, each of these produced indigo in good quantities. Well done, lads! Dr. Rakesh Jain has been given the Nova Nordisk Award for the year 2000 for this fine piece of work.With this, indigo technology in India has come a full circle, and I wonder whether indigo will now come from the Petri dish rather than the plant!
D. Balasubramanian
Send this article to Friends by
E-Mail
Sci Tech
|
