The prospect of kemiri sunan ( Reutalis trisperma B. airy shaw ) development as a source of bio-oil from inedible crops

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Introduction
Vegetable oil is one of the energy sources with great potential to meet the increasing energy needs.Along with the depletion of energy sources from fossil fuels, vegetable oil is a very potent energy source to be developed because this material is one of the renewable energy sources.Several types of plants that produce vegetable oil include palm oil (Elaeis guninensis), Kemiri sunan (Reutealis trisperma (Blanko) Airy shaw), tamanu (Calophyllum inophyllum), jatropha (Jatropha curcas L.), Kusum (Schleicher oleosa), Pongamia (Pongamia pinnata), and skunk tree (Sterculia foetida) [1].Based on its characteristics, vegetable oil is one of the sources of raw materials for various chemical and biodiesel industries.
Among the types of vegetable oil-producing plants as biodiesel raw materials with high yield potential and do not compete with food ingredients are Kemiri Sunan [2].The oil content in the kernel of the Kemiri sunan reaches 50%.Symptoms of poisoning due to consuming Kemiri sunan seeds cause digestive disorders, stomach pain, vomiting, and diarrhea [3].Furthermore, it is said that kemiri sunan seed extract significantly affects the autonomic nervous system by causing ptosis, impairing breathing, and affecting the central nervous system by reducing motor activity.However, according to the Hodge and Sterner toxicity scale, the Kemiri sunan seed extract was classified as in the sixth group, meaning it was safe [4].
One 8-year-old kemiri sunan tree can produce 100-150 kg of dry seeds, with a potential crude oil yield of about 6-8 tons/ha/year, depending on the varieties of kemiri sunan used and the agroecosystem development [5].As with the characteristics of vegetable oils in general, the oil produced from Kemiri sunan is a source of raw materials to be processed into various derivative products such as the oleochemical, biofuel, and other chemical industries.One of the derivative products of kemiri sunan oil is bio-diesel which has characteristics similar to diesel derived from fossil fuels so that it can be used directly as fuel for diesel engines.
In Indonesia, research and study of kemiri sunan from upstream to downstream have been carried out by both central and regional government agencies, universities, entrepreneurs, and interested parties [1,[6][7][8][9].In terms of plant varieties, the superior varieties have been released, namely Kemiri sunan-1, Kemiri sunan-2, Kermindo-1, and Kermindo-2 [10].The four varieties have advantages in terms of production potential and free fatty acid characteristics.Kemiri sunan can be cultivated using generative (seeds) and vegetative (grafting) plant material.Kemiri sunan fruit, after physiological maturity, will fall, so the collection of fruit is done by collecting it.Handling the results from peeling fruit skins, drying seeds, extracting oil from the kernel, to processing crude oil into biodiesel has been able to be carried out with relatively good results [1,11].However, research still needs to be done to improve efficiency from upstream to downstream.
Developing vegetable oil-producing plants in Indonesia has strategic value.However, the availability of land for the development of vegetable oil-producing plants is one of the obstacles faced.One of the opportunities that can be done is by utilizing marginal lands such as ex-mining and dry land with dry climates.
This paper seeks to collect the results of research on the development of technological findings to increase the usability of kemiri sunan as a source of non-food vegetable oil concerning energy fulfilment, especially for industrial, transportation, and other needs that until now are still very dependent on fossils.

Biofuel from kemiri sunan oil
In Indonesia, the need for biodiesel in the short term can be supplied from palm oil raw material, which currently produces 26 million tons.In the long term, using palm oil will impact food needs so that sources of vegetable oil are needed from other plants that do not interfere with food needs, including kemiri sunan.
To find alternative energy to replace fossil fuels, various parties have researched plants that have the potential as sources of biofuels.and Various studies have shown that the dry seed productivity of the Sunan Kemiri plant at the age of > 8 years can reach 100-150 kg/tree/year.With this productivity level at a plant population of 100-150 trees/ha, a dry seed production rate of 10-15 tons/ha/year can be achieved.This yield is equivalent to about 8 tonnes of crude oil/ha/yr or about 7 tonnes of biodiesel/ha/yr and 5,695 kg of milk cake residue per hectare per year [5].Kemiri sunan cake can be used to bio briquettes, biogas, fertilizer, and animal feed [12].
Biodiesel from Kemiri sunan is generally carried out through esterification and transesterification processes with a yield of 95.15% [11].Aunillah and Pranowo, have obtained the technology from the process by modifying the steps in the esterification process with the dry oil process which does not require a catalyst as in the esterification process [1].However, the transesterification process is carried out in two stages.Through this process, crude oil from kemiri sunan already has the characteristics required in SNI-04-7182-2006.The technology for the biodiesel production process uses the two-stage transesterification method, supported by the invention of the engineered multifunctional biodiesel reactor, which is capable of processing various types of crude oil [13].

Prospects of the oleochemical industry and other industries
Kemiri sunan oil, composed of several fatty acids, can be further processed into various oleochemical products with higher selling value.Oleochemicals are compounds obtained from the separation or breakdown and further reactions of oils and fats.These compounds can be in the form of fatty acids, glycerol, fatty acid esters, fatty alcohol, fatty amides, and fatty amines and their derivatives.
Currently, the Indonesian oleochemical industry relies on crude palm oil (CPO) as raw material to produce fatty acids, fatty alcohols, fatty esters, and glycerin and their derivatives.There are more than 20 types of oleochemical derivatives produced in Indonesia, such as fatty alcohol derivatives, alcohol sulfate, ethoxylate, and several other alcohol-based primary surfactants, namely alcohol ether sulfate, fatty alcohol ethoxylate, and fatty alcohol sulphate.However, when compared to Malaysia, Indonesia is still lagging, Malaysia's downstream industry can process oleochemical products into more than 120 types of high-value-added products.However, Indonesia has been able to master the various processes for the manufacture of oleochemical derivative products.
Kemiri sunan oil is a triglyceride composed of glycerol molecules and fatty acid molecules.The fatty acid composition of the constituents can be seen in Table 1.According to Vossen [12], kemiri sunan oil majority consists of α-eleostearic acid.

Utilization of kemiri sunan waste
In handling raw materials and extracting oil from seeds, waste is generated which can still be used for various purposes.Kemiri sunan skin is the largest part of the fruit, the amount can reach 65% of the whole fruit.The fruit peel contains nutrients N, P, and K, potentially as plants' fertilizer sources.The skin of this fruit is processed through composting by utilizing decomposing microbes into compost.In addition, the fruit skin can also be dried and then made into briquettes as fuel [13].It can be applied as feed to produce protein-rich biomass with additional endocarp (20 wt% cake and 80 wt% endocarp)endocarps [14].Glycerol, a by-product in biodiesel production, is a raw material for making soap and cosmetics.The process of producing briquettes, biogas, and soap from the by-products of fruit peeling and oil extraction and the process of making biodiesel.
Kemiri sunan cake can also be processed to produce biogas [12].The cake, a byproduct in the process of extracting oil from seeds, contains 5-10% oil so that it can still be used as an energy source by processing it into briquettes.In addition, the cake can also be used as feed to produce biogas.The skin (shell) of the Kemiri sunan fruit can be used for animal feed by converting black soldier fly larvae into biomass which has protein content (45% dry weight) and oil content (26.6% dry weight) [15].

Kemiri sunan spread
Kemiri sunan has a wide adaptability because this plant can grow well in various agroecosystem conditions.Until now, the kemiri sunan population that grows in Indonesia is still concentrated in Garut and Majalengka regencies, West Java.The agroecosystem conditions in the two districts are classified as wet climates.In these agroecosystem conditions, kemiri sunan grows and produces well and has a fairly high oil content [5].
These Kemiri Sunan plants have grown in 13 regencies, and most of them are in West Java Province.Sumedang Regency is the area with the largest area reaching 810 ha, followed by Bajawa in East Nusa Tenggara with 620 ha (figure 1), Buru Island in Maluku with 100 ha, and Kutai Kartanagara with 85 ha.The rest spread to several other districts, including Majalengka, Kuningan, Subang, Purwakarta, Bandung, Garut, Banjar, Pangandaran, and dan Bangka.

Ex-mining land utilization
Mining activities are generally carried out in an open-pit-mining manner, which causes the land surface (landscape) to become irregular.Mining waste on the surface of the land, such as overburden, tailings, and acid mine drainage, and rock waste containing heavy metals, often causes a decrease in land quality.
Various consequences that can be caused include disturbed microbial population and activity [16], and the soil becoming infertile and difficult to use for plant cultivation [17].The environmental damage faced is not only land but also water and groundwater surface, flora and fauna, and air pollution [18][19][20].Extraction of mineral materials by open pit mines often causes the mountain peaks to be cut off and create large holes.This mining technique is usually used to excavate thin, flat coal deposits near the ground surface.The consequences include poor physical, chemical, and biological conditions of the soil, for example, the soil layer is not profiled, bulk density occurs (compacting), lack of important nutrients, low pH, pollution by heavy metals on ex-mining land, and decrease in soil microbial population [21].The pH value of ex-tin mined soil is around 4.6 Total Organic Carbon (TOC) was 1.05%, and Total Nitrogen was 0.01% [22].For this reason, it is necessary to have an activity in an effort to preserve the environment so that no further damage occurs.This effort can be taken by rehabilitating it so that it is hoped that it will be able to restore the damaged ecosystem closer to or even better than its original condition.
The Kemiri sunan cultivation has been adapted, including in former coal mines in East Kalimantan, former tin mines in Bangka Belitung (figure 2), and former bauxite mines on Bintan Island.The growth and development of kemiri sunan on the land are considered quite good and are currently starting to produce.However, better plant performance was found on ex-coal mining land [5].This is possible because the former coal mining has better physical and chemical soil conditions than the ex-tin and bauxite mining areas.The kemiri sunan plant has an excellent tolerance in ex-gold mine land, the increased rate of photosynthesis evidence this compared to normal soil conditions.The high content of Ca, Mg, Fe, Zn, and Mn in ex-gold mines is a good stimulant for the growth of kemiri sunan [6].

Reservoir buffer land
The planting of kemiri sunan in reservoir buffer lands has been carried out, namely in Jati Gede Reservoir, Sumedang Regency, West Java, and Gajah Mungkur Reservoir in Wonogiri Regency, Central Java [5].The growth and development of plants on the land show a fairly good performance and have begun to produce.Reservoir buffer land is a very strategic area to maintain the existence of reservoirs, as well as the separator between reservoir areas and non-reservoir land.Damage to the buffer land will shorten the life of the reservoir.Rainwater from the catchment area, where the forest condition has been deforested will carry soil material into the reservoir without being prevented.

Dry land dry climate
The development of kemiri sunan to various areas that have a wider variety of dry land agroecosystems has been carried out since 2010.Research shows satisfactory results in some relatively extreme dry agroecosystem conditions, such as dry land with a dry climate and rocky soil conditions in East Nusa Tenggara.The vegetative and generative growth of the plants studied shows that the adaptation of this plant is very good with management following the recommended cultivation technology [10].

Conclusion
Kemiri sunan [Reutealis trisperma B. Airy Shaw] has good potential as a non-food vegetable oil-producing plant that can be used as a source of raw materials for the oleochemical, biofuel, and other derivative products industry.Biodiesel from Kemiri sunan oil has meet the standard SNI.
Constraints of limited land for the development of kemiri sunan can be overcome by utilizing less productive lands, including ex-mining land, dry climate dry land, and reservoir buffer land.The condition of the land is sufficient to support the growth and development of the kemiri sunan plant which is quite good.The plant's character is in the form of a tree with a shady leaf crown and a deep root system that makes this plant very useful as a conservation plant on these lands.

Fig. 1 .
Fig.1.The performance of kemiri sunan at the age of 24 MAP in a dry land with a dry climate[5].