Natural rubber is a plant-derived material that continues to be widely used today, and it is one of the crucial materials to achieve the sustainable society. Nevertheless, it should be noted that not all natural rubber is produced through sustainable practices. There are several global issues that need to be resolved to achieve the sustainability of natural rubber. These issues include the risk of pathogen spread in para rubber tree (Hevea brasiliensis), the balance between rubber production and biodiversity, and the long-term sustainability of rubber farmers, for example.

This review paper introduces these issues with academic research finding. Furthermore, it presents current research on alternative rubber-producing plants such as russian dandelion (Taraxacum kok-saghyz) and guayule (Parthenium argentatum), as well as research on the biosynthesis of natural rubber.

Bridgestone has launched a project in cooperation with WWF Japan to disseminate technology that improves the yield of natural rubber smallholders in the provinces of Riau and Jambi in Indonesia. By improving the livelihoods of smallholders through increased productivity, we aim to prevent deforestation caused by the development of new agricultural land, enhance the technical capabilities of smallholders supporting natural rubber production, and stabilize the supply of natural rubber. By providing instruction on correct tapping techniques and methods for collecting as cup ramp, we aim to improve yields. Additionally, we will introduce standardization of training methods and ‘farmer-to-farmer’ training.

Hevea brasiliensis, commonly known as rubber tree, is a crop primarily cultivated in Southeast Asian countries and serves as the main source of natural rubber. Natural rubber is an ecofriendly material and indispensable for many industries, including the automobile sectors. Its stable supply is increasingly important economically.

However, in recent years, decrease in its production caused by Leaf Fall Diseases (LFDs) has become serious problem in many Southeast Asian countries. LFDs cause characteristic lesions on natural rubber tree leaves and results in leaf drop, leading to a reduction of photosynthetic capacity and finally causes a significant decrease in natural rubber production. In Indonesia, reduction of natural rubber production by LFDs is very severe with about 800,000 tons annually since 2017. This review explains characteristics and pathogenicity of the fungi causing LFDs. We also explain our challenges to control them.

End-of-life tires (ELTs) represent a significant global environmental challenge due to their high volume, complex vulcanized structure, and resistance to biodegradation. While mechanical, chemical, and thermal recycling methods are established, their environmental impact and high energy demands have driven interest toward biotechnological approaches. Recent studies have identified key cis-1,4-polyisoprene-cleaving enzymes, Latex Clearing Protein (Lcp) and Rubber Oxygenases (RoxA, RoxB), and elucidated their molecular properties, cleavage patterns, and taxonomic distribution. Advances in understanding transcriptional regulation, particularly LcpR-mediated control, reveal conserved and divergent mechanisms across rubber-degrading bacteria. Downstream oxidation of oligo-isoprene aldehydes by aldehyde dehydrogenases (ALDHs) and OxiAB complexes is essential for complete rubber assimilation. Laboratory-scale biodegradation of unvulcanized rubber has achieved over 80% conversion under optimized enzymatic conditions, yet enzymatic degradation of vulcanized rubber remains largely unsuccessful. Challenges include sulfur cross-links, zinc oxide persistence, and additive toxicity, necessitating integrated physical–chemical pretreatments with multi-enzymatic systems. Drawing parallels to PET enzymatic recycling, recovery of oligo-isoprenoids for chemical upcycling presents a promising route for ELTs valorization. This review synthesizes current knowledge on enzymes, genetic regulation, and catalytic mechanisms involved in natural rubber biodegradation, highlighting both the potential and the technical bottlenecks in developing efficient, scalable bioprocesses for sustainable ELTs management.

This study re-examines the potential of natural rubber seeds—an underutilised by product of Hevea brasiliensis —as a feedstock for integrated biorefineries. After reviewing the biological and economic context of rubber cultivation in Southeast Asia, we analyse the morphology and chemical composition of the seeds. The oil-rich kernel contains 20–30% triacylglycerols with a C16–C18 fatty acid profile suitable for transesterification and hydroprocessing. The shell, comprising lignocellulosic material, was carbonised to produce biochar and biocoke, while the deoiled cake showed promise as a high-protein feed or fertiliser after detoxification. We report pilot-scale trials in Thailand that demonstrated efficient collection, drying and pressing using decentralised equipment, yielding rubber seed oil (RSO) with physicochemical properties comparable to other non-food oils. Life cycle and preliminary economic analyses suggest that valorising rubber seeds could diversify farmer income and reduce waste without competing with food crops. The findings highlight rubber seeds as a versatile resource for producing renewable fuels, biochemicals and soil amendments, paving the way for a circular bioeconomy in rubber-growing regions.