Biorefinery From Organic Waste As Circular Economy Strategy
Biorefinery has great potential for organic waste problems. Biorefinery is a circular economy strategy with great potential to be implemented in Indonesia. This is because Indonesia is a country that produces a lot of organic waste. In fact, according to The Economist Intelligent Unit 2021, out of all the G20 countries, Indonesia is in the category of countries producing the most organic waste along with Saudi Arabia, Brazil, Mexico and Turkiye.
Biorefinery as Circular Economy Solution
Biorefinery is a process for converting biomass into a variety of value-added products. The biorefinery concept is taken from the refinery concept in the oil and mining industry. The aim of implementing a biorefinery is to utilize biomass as efficiently and effectively as possible in order to produce diversified, high-value products. The processing stage of the biorefinery begins with the pre-treatment stage. Pre-treatment is divided into three, namely physical pre-treatment , chemical pre-treatment, and biological pre-treatment (aerobic and anaerobic).
Biorefinery of Organic Waste
Organic waste is waste that comes from agricultural products and wasted food. If left untreated, organic waste can have a negative impact on health and the environment. Therefore, biorefinery is a solution to dealing with organic waste while making it a profitable opportunity. The following are products that can be produced through the biorefinery process on organic waste:
Volatilisable Fatty Acids
VFAs or short-chain carboxylic acids such as acetic acid, propionic acid, butyric acid, isobutyric acid, and valeric acid. This type is very dependent on the organic waste material used. VFA applications are very broad, both individually and on an industrial scale. VFA can be used as food ingredients, pharmaceutical ingredients, to wastewater treatment.
Biomethane is a CH4 compound which is the main product of biogasification. Synthesis of Ch4 gas from organic waste can be a potential alternative energy. Factors that affect the amount of CH4 from organic waste include pH, temperature, C:N ratio, reactor design, type of inoculum, and amount of biomass. Indonesia is one of the countries included in the Digital Global Biogas Cooperation project which encourages the development of biogas and biomethane on a large scale.
Bioethanol is a product produced from the fermentation of organic waste. Sources of organic waste used are carrot waste, calcium alginate, and orange peel waste. This organic waste material needs to go through several stages such as pre-treatment, enzymatic hydrolysis, and fermentation in order to become bioethanol. Bioethanol can be used for motor vehicle fuel or as an additive to increase the octane rating of the main fuel. Thus, bioethanol can become bioenergy which can also reduce CO2 emission and replace fossil fuels which are currently less available.
Butyl alcohol or biobutanol is a precursor, solvent, eluent and extractant for other chemicals. Biobutanol is an alcohol type with a C-4 bond with a C4H9OH chain. This substance is extracted from starch-rich biomass such as rice, corn, and wheat. The method used to produce biobutanol is by several pre-treatments and processing the biomass using the bacterial fermentation of Clostridium acetobutylicum.
Biopolymers are produced from secondary metabolites of various prokaryotes such as bacteria as a response to scarcity of nutrients and stress. For example, the bacterium Halomonas boliviensis which is stressed on food waste, cane molasses, or bread waste, they will produce polyhydroxyalkanoates (PHA). Biopolymers can be used for edible coatings, emulsions, bioplastic, packaging materials in the food industry, and as drug transport materials, medical implants such as medical implant organs, wound healing, tissue scaffolding, and dressing materials in the pharmaceutical industry.
Biofertilizer is a solution to dealing with organic waste that is safe, effective, and profitable from an economic and environmental perspective. The use of biofertilizers in agriculture will replace the use of synthetic fertilizers and reduce soil and water pollution. Organic waste can produce biofertilizer either in solid or liquid form. To produce quality compost it is important to pay attention to pH, temperature, humidity, aeration and C:N ratio. Composting can be done aerobically or anaerobically. An example of pre-treatment for composting organic waste is by fermenting the bacteria Brevibacillus borstelensis.
Biohydrogen is a futuristic material produced from photo-fermentation, bio-photolysis, or a combination thereof. This H2 product also comes from by-products of acetogenic bacteria. Biohydrogen can be used as an alternative energy to replace fossil fuels. Therefore, the development of biohydrogen production in terms of types of biomass, pre-treatment techniques, pH, reactor configuration is a factor that can be studied further.
Utilization of biorefinery to produce various products from organic waste is a promising solution. Biorefinery on organic waste not only has an impact on reducing organic waste and reducing the adverse effects of organic waste. However, biorefinery can also maximize the value of biomass so that it can increase company revenue and increase economic stability. Biorefinery will also eventually become an opportunity for increased employment through innovation in diversifying available biomass products.