Isolation of nanocrystalline cellulose from tunicates

Abstract

Nanocrystalline cellulose (NCC) is a high value product, which consists of the nanoscale crystalline region of the cellulose polymer. Tunicates are marine invertebrate animals, comprised of tunic tissue, which acts as a skeletal structure, and internal organs. Tunic tissue is the only known animal source of NCC. Tunicates require a support to grow and spawn, which they find in the form of mussel socks in Prince Edward Island (PEI). This greatly affects mussel yields, and has become a nuisance to island fishermen. The present work is studying the feasibility of producing high value NCC from tunicates. Representing the first time tunicates have been utilized as a resource on PEI. NCC is isolated using prehydrolysis-kraft cooking-bleaching method. The yield of NCC from Vase and Club tunicate is 44 ± 8% and 32 ± 7% respectively. Club sourced NCC was determined to be 89 ± 7% crystalline as compared to 73 ± 6% from Vase. The average length of NCC was higher in the case of club (1567 ± 638 nm) than vase (1374 ± 600 nm), leading to aspect ratios of (90 ± 57) for club and (80 ± 60) for vase tunicates. The characterization of the obtained NCC by; powder X-ray diffraction (XRD), transmission electron microscopy (TEM), energy dispersive X-ray spectroscopy (EDX) and thermogravimetric analysis (TGA) are discussed in the paper.