Location: Bioproducts ResearchTitle: Thermomyces lanuginosus STm: a source of thermostable hydrolytic enzymes for novel application in extraction of high-quality natural rubber from Taraxacum kok-saghyz (rubber dandelion)
|SIKANDAR, SHOMALIA - The Ohio State University|
|UJOR, VICTOR - The Ohio State University|
|EZEJI, THADDEUS - The Ohio State University|
|ROSSINGTON, JESSE - The Ohio State University|
|MICHEL, FREDERICK - The Ohio State University|
|ALI, NAEEM - Quaid-I-university Islamabad|
|CORNISH, KATRINA - The Ohio State University|
Submitted to: Industrial Crops and Products
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/29/2017
Publication Date: 4/10/2017
Citation: Sikandar, S., Ujor, V.C., Ezeji, T.C., Rossington, J.L., Michel, F.C., Mcmahan, C.M., Ali, N., Cornish, K. 2017. Thermomyces lanuginosus STm: a source of thermostable hydrolytic enzymes for novel application in extraction of high-quality natural rubber from Taraxacum kok-saghyz (rubber dandelion). Industrial Crops and Products. 103(2017):161-168. doi:10.1016/j.indcrop.2017.03.044.
Interpretive Summary: Taraxacum kok-saghyz (TKS, Kazakh dandelion) is under development in the US as a source of domestic natural rubber. Rubber in TKS is isolated from root tissues, usually by grinding in aqueous solvent. Pre-treatment of root tissues with Thermomyces (natural fungus) enzymes effectively soften the root tissue to allow more rubber to be extracted. Importantly, this newly-isolated fungus lives naturally in warm environments (isolated from self-heating garden compost) so performs well at higher temperatures (55 'C). In addition, this study showed the Thermomyces fungus can also break down wheat straw and guayule bagasse, so provides alternatives to chemical pretreatment when these materials are used for biochemical or biofuel production.
Technical Abstract: Hydrolytic enzymes from a newly isolated strain of the thermophilic fungus Thermomyces lanuginosus were used to extract rubber from Taraxacum kok-saghyz commonly known as rubber (or Russian or Kazak(h)) dandelion. The fungus was isolated from garden soil and identified as Thermomyces lanuginosus STm based on 18S rRNA gene sequence analysis. The isolate produced considerable amounts of extracellular hydrolytic enzymes on lignocellulosic substrates at 55 'C incubated for 8 days in 150 mL shake flask experiments. The maximum enzyme activities on wheat straw and guayule bagasse were: xylanase (167.41; 130.1 U/mg), inulinase (69.8; 34.1 U/mg), cellulase (carboxymethyl cellulase) (16.7; 4.8 U/mg), filter paper assay (FPase) (14.2; 5.5 FPU g-1) and pectinase (7.2; 3.2 U/mg), respectively. In addition, alkali-pretreated roots of Taraxacum kok-saghyz (TK), incubated with crude enzyme extracts from T. lanuginosus STm grown on guayule bagasse, subsequently yielded more natural rubber (90 mg/g dry TK root) than previously established protocols, Eskew process (24 mg/g) and commercial-enzyme-combination process (45 mg/g). Rubber purity in the T. lanuginosus STm treatment was 71.7%, greater than the Eskew process at 37.5%. However, the crude T. lanuginosus STm enzyme treatment at 91.6% rubber purity approached the purity of the commercial-enzyme-combination process at 94.1% purity.