Valorisation of Proteins from Rubber Tree

PURPOSE: The objective of this study was to identify the availability, possible applications, and economic potential of proteins that are present in different parts of the rubber tree. Proteins from non-food sources can be used in e.g. animal feed or biochemicals production with no or little competition with food production, rendering them important biobased feedstock. Rubber tree is primarily grown for its latex that is used in rubber production. Indonesia has the largest rubber plantation area that is mostly owned and run by smallholder farmers. Using non-latex fractions from the rubber tree may generate additional income, and increase the economics of rubber plantations in general. METHODS: Several biomass streams from the rubber tree and subsequent latex processing were considered. Data were compiled from literature, a case study, and interviews with researchers, smallholder farmers, and managers at rubber processing plant and plantation. RESULTS: Latex waste streams, seeds, and leaves were considered to have the highest potential based on the amount of available proteins, and processes to isolate proteins from these streams were proposed. Isolation of specific functional properties from natural sources requires complex (and expensive) separation processes and therefore only economically feasible when specific use of the protein(s) for high value applications can be identified. Purification of many interesting proteins from latex fractions has already been described. Processing of seeds and leaves may also yield useful proteins for food, other purposes, and also still unknown high value applications. CONCLUSIONS: A biorefinery concept can be applied to obtain multiple products from the seeds and leaves, and protein extraction can be performed with available knowledge and technology. Small scale processing can be more beneficial for the farmers, especially if the products are used locally for feed.