Unlocking Indonesia’s Green Gold Potential: Tapping into Sago Palm for a Renewable Chemical Industry
In the heart of Indonesia, a remarkable plant called Sago (Metroxylon sagu Rottb.) reigns supreme. Belonging to the palm family and falling under the Spadiciflora order, Sago is a homegrown treasure that has been a source of carbohydrates for the Indonesian people for generations (Directorate General of Estate Crops, 2019). This indigenous plant is mainly celebrated in the eastern regions of Indonesia, thriving in Papua and Maluku. What sets Sagu apart is its impressive productivity. In the realm of carbohydrate-producing flora, such as sweet potatoes, corn, rice, and cassava, Sago stands as a true champion, yielding significantly higher quantities of the sought-after starch. It can produce 150–300 kilograms of dry starch per plant (Pei-Lang et al., 2006).
As our world undergoes rapid transformation, with the global population expected to surge to 9.7 billion by 2050 — an astonishing 23% increase from today (United Nations Department of Economic and Social Affairs, 2019) — our needs are evolving. With rising incomes per capita, there is an inevitable surge in the demand for carbon used in chemicals. According to Kähler et al. (2021), this demand is projected to climb from 450 million metric tons annually in 2021 to a staggering 1000 million metric tons annually by 2050. However, there’s a significant challenge at hand. The chemical industry’s current reliance on fossil-based petrochemicals is not sustainable in the long run. Fossil resources, the primary feedstocks of organic carbon for the chemical industry, take millions of years to form and are, therefore, non-renewable. As Ewing et al. (2022) pointed out, these resources cannot be readily replenished within a reasonable timeframe, making them finite.
We must transition towards renewable resources in the quest for a sustainable future. To maintain our high standard of living and ensure a continuous supply of chemicals and materials, we must explore alternative organic carbon sources. In this context, Indonesia’s untapped Sago palm could emerge as a game-changer in pursuing renewable feedstocks for the chemical industry.
Sago’s Starch Potential
In addition to its crucial role in providing sustenance, Metroxylon palms, including sago palms, have long been considered unexploited or underexploited bioresources (Ehara, 2018). The different species of Metroxylon palms possess varying starch contents, with Metroxylon sago standing out as the star performer, boasting the highest starch content among its counterparts (shown in Table below). The information regarding Metroxylon sago aligns with the author’s individual laboratory examinations, revealing that the starch content within sago pith falls within the range of approximately 60% to 75%.
Sago palm, particularly Metroxylon sagu, exhibits a fascinating pattern of starch accumulation within its trunk. Notably, sago starch granules present a considerable size distribution, ranging from 10 to 50 μm in diameter while exhibiting an average granule diameter measuring 32 μm. Moreover, starch tends to accumulate from the base upward, with the pinnacle of starch content reaching the flowering stage known as ‘Angau Muda’. This stage is estimated to occur approximately 12.5 to 13 years from planting (Karim et al., 2008). At this stage, the starch content in the finer fraction (passing through a 200-mesh sieve) peaks, typically ranging from 39% to 41.3% on a dry weight basis (Pei-Lang et al., 2006).
Despite not specifying the growth stage, Duque et al. (2018) reported an even higher figure, with 88.31% of total starch content passing through a 60-mesh sieve. Moreover, they discovered that employing finer mesh sizes and sieving techniques on pith flour could isolate starch and enhance its purity. In particular, they achieved an impressive 96.62% starch purity on a dry basis using a 200-mesh sieve, all while reducing polyphenol content to a mere 0.33%. The revelation of lower polyphenol content is particularly noteworthy as polyphenols, being antioxidants, can impact biobased processes, such as fermentation. This suggests that sago palm’s starch can hold immense potential for use in biobased processes, making it a valuable candidate in the pursuit of renewable resources for the chemical industry.
Sago Abundance in Indonesia
As of 2018, Indonesia’s sago palm cultivation encompassed a substantial 311,954 hectares, primarily within managed sago palm plantations (Directorate General of Estate Crops, 2019). This extensive landscape was predominantly composed of smallholder plantations, spanning 299,366 hectares, constituting approximately 95.96% of Indonesia’s overall sago cultivation area. Conversely, large private plantations occupied 12,588 hectares, accounting for 4.04% of the total area. Notably, this marked a growth of 1.68% from the preceding year, with an additional 5,149 hectares integrated into sago palm cultivation in 2018. It is essential to emphasize that these figures exclusively pertain to managed sago palm plantations, situated within Indonesia’s broader sago forest expanse, which encompasses approximately 5,259,538 hectares in Papua and West Papua alone. (M. Bintoro et al., 2013; M. H. Bintoro et al., 2018)
Four of the Indonesian provinces stand out with the most extensive sago palm populations. These provinces include Aceh, Riau, South Kalimantan, and Papua. Papua province, in particular, boasts Indonesia’s largest sago palm cultivation area, spanning an impressive 155,943 hectares. However, despite its vast land area devoted to Sago, Papua’s productivity stands at 1,726 kg/ha/year, starkly contrasting to Riau, which records a productivity of 7,273 kg/ha/year. This discrepancy can be attributed to the untamed nature of sago lands in Papua compared to the organized and managed sago plantations in Riau. As a result, Riau claims the title of the largest sago producer in Indonesia, contributing a significant 80.99% of the total sago production in the country. Papua, Maluku, and South Kalimantan follow, with respective contributions of 12.35%, 2.02%, and 0.93%.
The productivity of Sago in Indonesia has experienced fluctuations over the years, particularly during the period from 2014 to 2020. The average annual growth rate was approximately 2.43% during this time frame. From 2014 to 2016, national sago productivity witnessed an annual average decline of 10.23%, reaching its lowest point in 2016 at 3,377 kg/ha. However, between 2017 and 2020, sago productivity demonstrated more stability. Achieving sustainable, maximum sago productivity requires transforming sago management practices from “wild sago forests” to organized sago plantations. This involves improving sago populations’ distribution and age composition through initiatives such as organizing smallholder sago plantations. Furthermore, expanding sago cultivation in potential regions can further enhance Indonesia’s national sago productivity
Eco-Friendly Advantages of Sago Palm Cultivation
Within the vast realm of sustainable agricultural practices, Sago palm presents as a fascinating and multifaceted bioresource with many environmental advantages. Its cultivation extends far beyond a mere source of sustenance, as it can address critical environmental concerns (H. Bintoro et al., 2010; M. Bintoro et al., 2013; M. H. Bintoro et al., 2018).
Soil Subsidence
Sago palm plantations offer a viable solution to counteract the degradation of peatlands, primarily due to their water level maintenance practices. Thriving in swampy, waterlogged, and peatland conditions, sago palms necessitate waterlogged environments during their growth stages, indicated by the vibrant green coloration of their leaves. By sustaining optimal water levels throughout the sago palm’s growth cycle, the degradation of peatlands can be effectively mitigated.
The Absorption of CO₂
The capacity of sago palms to absorb carbon dioxide (CO₂) plays a pivotal role in environmental preservation. Calculations indicate that sago palms can sequester approximately 240 metric tons of CO₂ per hectare annually. Furthermore, sago palms contribute to carbon storage in peatlands, effectively reducing greenhouse gas emissions. Peatlands emit gases like CO₂ and CH₄ at rates ranging from 25 to 200 milligrams per square meter per hour, while sago palm photosynthesis absorbs 22 milligrams of CO₂ per square decimeter per hour. In total, sago palms spanning 5,259,538 hectares in Papua and West Papua provinces have the potential to absorb a staggering 1,262,289,120 metric tons of CO₂. Furthermore, sago palms excel in CO₂ absorption compared to other major crops, emphasizing their significance in environmental preservation (as shown in the Table below).
Water Conservation
Due to their great tolerance for waterlogging and ability to survive without soil drainage, sago palm cultivation offers a sustainable solution to the deterioration of peatlands. Sago palms flourish in persistently humid soil, which helps them save water in the soil. Sago palms require high soil humidity, making them ideal for cultivation in areas that occasionally flood. Sago palm plantations, in particular, save water and preserve the soil’s structure. Water drainage, which sends surplus water toward rivers or the sea, is important if the area is intended for other crops. Water is saved and the overall ecological balance is preserved when sago palms are grown on peat soil.
In Conclusion
The Sago palm (Metroxylon sagu Rottb.) stands as an extraordinary indigenous resource, holding the potential to revolutionize the chemical industry and contribute to a sustainable and environmentally conscious future. Its impressive starch yield, coupled with its extensive cultivation in Indonesia’s swampy regions, makes it a promising renewable feedstock for the chemical industry. Moreover, the implementation of organized Sago palm plantations offers the prospect of increased productivity, rural development, and sustainability. Beyond its economic potential, the cultivation of Sago palm brings invaluable environmental benefits, including mitigating soil subsidence, conserving water resources, and absorbing substantial amounts of CO₂. These advantages underscore the Sago palm’s pivotal role in addressing the growing demand for renewable resources and its contribution to the preservation of delicate ecosystems and reduction of greenhouse effects. As we navigate the challenges of a rapidly expanding global population and an imperative to reduce our environmental footprint, the Sago palm emerges as a beacon of hope, offering a path towards a more sustainable and harmonious coexistence with our planet.
Feeling curious about the endless possibilities of Sago palm? Stay tuned for more captivating insights and discoveries about this remarkable resource. In the future, we’ll delve deeper into the fascinating world of Sago and explore how it can shape a more sustainable and vibrant future for all of us.
References
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