Chemistry and applications of lac and its by-product

Abstract

Lac is a natural resin secreted by Indian lac insect, Kerria lacca (Kerr), which thrives on the tender twigs of specific host trees. Lac is collected as the minor forest produce and cultivated since time immemorial in India, and lac cultivation is an important source of income for livelihood of the forest and sub-forest dwellers of central and eastern India. Lac still enjoys the monopoly of non-toxic, biodegradable, natural and safe resin and used for applications in pharmaceuticals, cosmetics and surface coatings for variety of uses in industries. India is the largest producer, processor and exporter of the lac, having average production of 20, 000 tons for the last 5 years. Organized research on lac was started in India after realization of its commercial potential worldwide. Research as well as documentation on all aspects of production, processing, product development and use diversification of lac has led to generation of authentic information. During processing of lac, various economically important by-products are obtained. The major component of lac is resin (65%) followed by two important by-products, viz. lac dye (1%) and lac wax (5-6%). The lac resin is processed into various value-added forms as per the need of the different industrial applications. Similarly, the dye and wax find its application in various sectors such as pharmaceutical, textile, etc. This chapter covers processing, chemistry of lac and its by-products and industrial and other applications, and also on outlining the future scope of the work.