Taraxacum kok-saghyz (TK): compositional analysis of a feedstock for natural rubber and other bioproducts

Abstract

Abstract Natural rubber (NR) is a critical raw material primarily produced in Asia from a single plant species ( Hevea brasiliensis ). This lack of biologic and geographic diversity, coupled with increasing demand, makes it imperative that alternative sources of NR are developed. Taraxacum kok-saghyz (TK) is a rubber-producing dandelion being developed as an alternative to the traditional source of NR. In order to improve the value of this crop and make it competitive with other sources of NR, germplasm improvement, crop production optimization, efficient extraction and purification methods and the valorization of TK co-products are needed. In this study, a compositional analysis of field-grown TK roots was conducted in which total solids, ash content, protein, crude fat, fatty acids, carbohydrates, lignin, and total water-, acetone-, and hexane-extract (rubber) were quantified and characterized. Mass closure was greater than 95%. The analysis showed that 5.4% (g/g root dw) of the root consisted of rubber and 1.7% was acetone extractable (mainly sterols). Approximately 60% (g/g dw) of the root was hot water extractable. Soluble sugars (32%) and proteins (10%) were the most abundant water soluble fractions. Inulin (18%) and sucrose (10%) were the most abundant sugars. Insoluble components included cellulose 9% (glucan), hemicellulose 7% (xylan, mannan, arabinan, galactan), lignin 5%, protein 5% and pectin 3%. This compositional analysis provides a baseline which can be used to assess compositional changes induced by altering plant genetics, environmental conditions and cultivation practices. Based on these results, pathways for TK processing are proposed, and its potential as a biorefinery feedstock is evaluated. This analysis indicates that TK has potential as a source of not only NR but other products and/or raw materials of importance including inulin and proteins.