The development of bio-based plastics or bioplastics as an alternative to conventional, fossil-based plastics gives hope that such problems can be solved with an additional advantage of reducing the use of fossil resources as agricultural feedstocks are used to produce bioplastic resins. Bioplastics can easily be produced from renewable biomass feedstocks through microbial fermentation and other bio-chemical based processes. These bioplastics can be fully degraded under suitable conditions, aerobic condition with temperature of below 60 ◦C and 80% humidity in composting facilities.Bioplastics are plastics derived from renewable biomass sources, such as vegetable fats and other organic oils. The production and use of bioplastics is sometimes regarded as a more sustainable activity when compared with plastic production from petroleum. Bioplastics are thermoplastic compounds which, unlike products of the petrochemical industry, are biodegradable. They have the further advantage that they can be produced from renewable resources. They are normally highly crystalline, optically active and possess piezoelectric properties.
Currently, the production capacity of conventional plastics worldwide is about 350 million ton annually. According to the market data of bioplastics provided by European Bioplastics, the global capacity of bioplastic production was 2.05 million tons in 2017, accounting for 0.6 percent of plastics produced. However, it has been forecasted to reach 2.44 million tons in 2022. Asia is the hub of bioplastics production, where about 56% of bioplastics were produced in 2017. Bioplastic derivatives can therefore replace a significant portion of plastics within the market at the moment.
These bioplastics have critical roles in a number of applications but mainly, the disposable plastics are used as packaging material. Packaging plays a significant part in recent years as over 67 million tons of packaging waste resulting in environmental concerns. This provokes many different processing, for example the using of additives such as fillers, colorants and plasticizers to produce polymers as packaging applications.
But there are challenges in the development of bioplastics as their high cost of production leads to certain limitations. An alternative for a low cost and renewable substrate has been proposed by using agriculture waste, agricultural residues and different other forms of carbon based plant material. Starch is especially important in this case as it one of the best materials for bioplastic production. In addition due to its performance and abundant sources, starch from agriculture waste is the solution for an alternative. Starch as biodegradable polymer becomes reasonable material for the production of bioplastics because of its low cost. Therefore, production of starch based bioplastics is the breakthrough innovation that can solve the environmental issues by using renewable and degradable natural resources and to provide more cost effective bioplastics.
Utilization of organic waste such as cassava peel for production of starch based bioplastic can also help reducing the environmental damages that are caused by conventional plastics and that could arise from utilization of food for plastic production. Higher value bioplastics can be obtained by improving their properties with the most abundant and biodegradable reinforcing filler like cellulose. What remains to be done is the developing industrial processes for sustainable production of bio-plastics from different forms of biomass including microalgae. In addition, possibilities to produce other products like fibers are also possible along bioplastics making a range of derivative products possible.
For the bioplastics to be practically viable, consideration of environmental impacts alone may not be sufficient. Interest should be given to economic impacts as well. There are studies that have emphasized the economic impacts of bioplastic production systems, particularly on cost benefit analysis of bioplastics production. However, these studies lack consideration of the overall life cycle stages of the bioplastics system or considered either environmental impacts or economic impacts, but not both
Related to bioplastics, several different arguments have been raised against the use of biofuels and their role in our future energy supply. These arguments have been mainly related to issues of costs, food versus fuel, and lack of sustainability. Besides this, the issues of alternative fuels, energy conservation and management, energy efficiency, and environmental protection have become important in recent years. Biodiesel is a one of the alternatives, which is being used in large quantities in transport, agriculture, industrial, commercial, and domestic sectors. Biodiesel is safe to handle and transport because it is as biodegradable as sugar and has a high flash point compared to petroleum diesel fuel. Biodiesel can be used alone or mixed in any ratio with petroleum diesel fuel. The idea of using alternative fuels has been widely spreading for many years now as a replacement for fossil fuels. The importance of this idea came from the large scale utilization of fossil fuels in mechanical power generation in various sectors, like agriculture, commercial, domestic, and transport sectors, and the continuous rise in fuels cost and their eventual unavailability in future.
These days, used cooking oils from restaurants are re-used by street sellers to fry their food. Those waste oils are commonly just thrown away without any treatment and have potential to pollute the environment. One of the ways to treat the waste oil is by converting to biodiesel to power domestic and farm based processes. Thus investigation into newer routes of biodiesel production and synthesis from such oils is a key research area especially due to the fluctuations in the conventional fuel prices and the environmental advantages of biodiesel.
Biodiesels are monoalkyl esters of long chain fatty acid derived from renewable lipid feedstock. The interest of this alternative energy resource is that the fatty acid methyl esters, known as biodiesel, have similar characteristics of petrodiesel oil which allows its use in compression motors without any engine modification. However, using vegetable oil to replace fuel has disadvantages related to the food versus fuel challenges all over the world. So the idea of using waste vegetable oil (WVO) has been introduced as an economical solution which also gives a waste management solution.
The use of used vegetable oils and their derivatives is one of the most reasonable solutions. However, the direct use of vegetable oils in diesel engines is impractical due to several factors, such as the high viscosity, acid composition, and free fatty acid content. Accordingly, they require further modifications for effective use through transesterification reaction is the most favorable for decreasing oil’s viscosity and producing “biodiesel fuel”.
Transesterification is a process of transforming triglycerides in vegetable oils into a mixture of fatty acid esters using alcohol and catalyst to speed up this reaction and to obtain high biodiesel yields. Methyl or ethyl esters are obtained, with much more similar properties to those of conventional diesel fuels. The main byproduct obtained is glycerol. The most common alcohols used for biodiesel production are methanol ethanol, propanol, isopropanol, and butanol. In presence of excess alcohol, the foreword reaction extends beyond the reverse reaction. Many catalysts could be utilized in the process; however, it was confirmed that transesterification is completed faster using an alkali catalyst. The mechanism of transesterification shows some challenges regarding this process, starting from the limitation of reaction rate by mass transfer between the immiscible oil and alcohol besides the reversibility of the transesterification itself which limits the conversion and consequently increases the reaction time and cost.