Silkworm rearing

A. mylitta. Tassar is a multivoltine type of silk and is mostly produced by tribal by rearing silkworms on forest plants Terminalia arjuna, Terminalia tomentosas and Shorea robusta). Tassar silk fibre has its own distinctive colour and is coarse to feel but has higher tensile strength, elongation and stress-relaxation values than the mulberry silk fibre secreted by Bombyx mori. 

There are all sorts of silk that are found in nature. The stuff that is usually found in textiles comes from silkworms (Bombyx mori). They are not really worms, but the larvae of moths. They emerge from very small eggs with an incredible lust for mulberry leaves, which they consume until they are ready to. pupate and weave a cocoon around themselves. Unlike spiders, which spin silk from their rear end, silkworm silk is actually hardened saliva, which comes out of the mouth. The larva has a small spinneret on its lip, through which the silk emerges. The cocoon is formed from a single strand of silk that... 

Traditional rearing of silkworms has been in practice in the country for centuries as silk continues to remain a sought-after commodity from India. The Department of Biotechnology has been supporting a number of projects in mulberry and non-mulberry sericulture. A few important features of such efforts are briefly described below. 

Over 90% of commercially produced silk is by the domesticated silkworm Bombyx mori. This is a monophagous insect with a diet that is restricted to the leaves of white mulberries, Moms alba and Moms indica. The production of silk requires the maintenance of mulberry plantations (moriculture), the rearing of silkworms to the cocoon spinning stage (sericulture) and finally the unravelling of cocoons (reeling). Each subsection of the production will be outlined below. 

Leaves are the primary output of moriculture, with woody biomass from shoot and trunk growth being the principal coproduct. Leaves unsuitable for silkworm rearing are secondary coproduct and are generally used as fodder for livestock (Madhu Prasad... 

Leaves unsuitable for silkworm rearing are generally fed to hvestock. We have modelled them as a substitute for intensive hay (Ecoinvent), as mulberry leaves have nutritional properties similar to alfalfa hay (Doran et al., 2007). Mulberry woody biomass is treated as a substitute for eucalyptus firewood, with corrections for lower HHV. Rearing waste is assumed to reduce the need of imported FYM, as they have a similar composition (Dandin et al., 2003) and composted waste makes effective fertili2er for mulberry. There are few products directly comparable to pupae, sUk, and silk waste from reeling that are exclusively allocated based on their economic value. 

Silks are fibrous protein, some forms of which can be woven into textiles. The best known type of silk have a range of functions, including cocoons of the larvae of the mulberry silkworm. Bombyx mori are reared in captivity [41, 143, 145]. They have repetitive protein sequence [29] with a predominance of alanine, glycine and serine (which is high in silkworm silks but low in spider silks). Silk proteins are comprised of four different structural components (1) elastic [3-spirals, (2) crystalline P-sheets rich in alanine, (3) tight amino acid repeats forming a-helices, and (4) spacer regions [47, 126]. 

---