Superior Pectinase for Processing Industrial Hemp and Other Agro-Fibres

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Objective(s)

The objective of this National Research Council Canada (NRC) project is to develop an improved pectinase (pectin-degrading) enzyme with superior performance characteristics for the efficient extraction of hemp and other agro-fibres by enzyme processing contrary to conventional chemical or other harsh treatments. The pectinase enzyme will be produced by protein engineering of a known pectinase or genomic screening of additional effective pectinases derived from microbes colonizing diverse habitats.

Description

Industrial hemp is 4.5 times more efficient in the conversion of atmospheric carbon dioxide (CO₂) into biomass in comparison to forest resources and can significantly reduce the reliance on petroleum and forestry as sources of industrial feedstock for use in the textile industry and as light-weight materials, e.g. in the automobile industry. Pectin degradation requires the combined action of several pectinases that consist of depolymerases (polygalacturonase and pectate lyase) and methylesterases. Despite its wide commercial application in the food industry, the functionality of pectinase at a low pH is detrimental to fibres. This project consists of developing a superior pectinase enzyme with higher performance efficiency in particular, capable of functioning at a higher pH (optimally near neutral pH or higher) and temperature for the extraction of long hemp fibres. Relevant bacterial or fungal pectinase genes will be selected using genome database mining as an economical approach for gene discovery. A selected number of gene candidates will be cloned, expressed in appropriate bacterial and/or fungal expression systems, and characterized for their biochemical properties that include substrate specificity, pH profiles, temperature optima, and stability. Selected candidates will be pursued further through a protein engineering approach by inducing mutations using site-directed mutagenesis or directed evolution to arrive at a best possible biocatalyst. Challenges anticipated by this research include gene expression in a heterologous system (e.g. genes derived from a different host or genetic background may not be readily expressed compared to its native or "homologous" system); and especially, production of the requisite biocatalyst at low cost for large scale application.

Structure of Xanthomonas Pectate
Lyase

Significant Outcomes

New knowledge and technology to develop a superior pectinase enzyme or formulation will allow for the efficient extraction of plant fibres and contribute to the commercial utilization of hemp and other agro-fibres. The pectinase enzyme produced is anticipated to function at a more optimal pH and/or temperature range during enzyme processing and is likely to generate consistency in fibre quality and increased strength. Considerable environmental impact and savings are expected including the reduction of emissions into water supplies and implementation of energy saving strategies from the use of enzyme processing as an alternative to traditional industrial processes.