Contribution of Fermentation Technology to Building Blocks of Bioplastics
Introduction
The extensive usage of plastics derived from petroleum has highlighted the need for sustainable substitutes made from renewable resources. As an eco-friendly and acceptable alternative, bioplastics have garnered a lot of interest. Bioplastics may dissolve back into carbon dioxide, thus they are not bad for the environment. Additionally, the polymers made from bio-based materials are more carbon-neutral and produce fewer greenhouse gases during production. They do, however, have several drawbacks, including as high production costs and inadequate mechanical qualities.
Bioplastics are a type of plastic that are created from natural and renewable biomass sources, including sugarcane, maize starch, wood, waste paper, vegetable oils and fats, bacteria, algae, and any type of agricultural waste used as an affordable and reusable substrate in bacterial fermentation. Therefore, switching from traditional plastic to renewable plastic will help to create a society, economy, and environment that is more sustainable.
The extensive usage of plastics derived from petroleum has highlighted the need for sustainable substitutes made from renewable resources. As an eco-friendly and acceptable alternative, bioplastics have garnered a lot of interest. Bioplastics may dissolve back into carbon dioxide, thus they are not bad for the environment. Additionally, the creation of plastics made from bio-based materials produces fewer greenhouse gas emissions and is more carbon-neutral. They do, however, have several drawbacks, including as high production costs and inadequate mechanical qualities.
General method for Bioplastic manufacturing
Polymers generated from plant materials, such as starch, cellulose, oils, and lignin, are used to create bio-based plastics. Plastic packaging made of bio-based polymers can behave similarly to the plastic of the traditional variety. Additionally, it can be utilized to create compostable and biodegradable polymers. Both kinds are known as bioplastics. Wood and annual plants (cellulose, lignin, hemicellulose), maize, wheat, potatoes, rice, tapioca, sunflower, rapeseed, etc. (starch, vegetable oils, proteins), sugar from sugar beet and sugarcane (biosynthesis: PLA, PHA, dextran, pullulan, xanthan), and sugar from these sources are among the renewable raw materials that are frequently used to produce biodegradable plastics and compostable biopolymers. However, even though starch and cellulose are not naturally plastic substances, they can be transformed into them through inventive fermentation methods or by the use of polymer technology with methods including casting, internal mixing, extrusion, and injection moulding. Plant leftovers have a reputation for being environmentally beneficial and having no negative effects on the flora or fauna. Cattle feeding is the best-reported use of these agricultural wastes (AW). These natural residues have drawn attention to the creation of affordable bioplastics due to their ample availability and non-commercial importance.
One of the most discussed classes of optically active biopolymers is termed Polyhydroxyalkanoates (PHAs), and because of their physical characteristics and biodegradability, they have the potential to replace some petroleum-based plastics. PHAs have displayed some quite striking similarities to the well-known synthetic polymers, low-density polyethylene, and polypropylene, and their disposal as bio-waste has made them more and more alluring in the quest for the development of biodegradable plastics that are sustainable. These PHAs made up of a group of naturally occurring polyesters that have been accumulated intracellularly by a number of microorganisms in the form of intracellular granules and stored as a reserve of carbon, energy, and reducing power in response to environmental stress or nutrient deficiency. PHAs have reportedly been found to disintegrate via intracellular depolymerase and then be metabolized as a carbon and energy source under the circumstances of carbon supply depletion.
Cupriavidus necator, a model strain that can be utilized to produce biopolymers in this blog, the carbon source glucose was compared to agricultural waste as a cheap and renewable carbon source in bacterial fermentation. The significance of mixing in manufactured bioplastics is also discussed.
Steps taken for producing bioplastics in the fermenter:
· Media pour
· Addition of microorganisms
· Quick screening for PHB production
· Microbial fermentation
· Recovery of PHB
· Quantification of PHB
· Blending of polymers and film fabrication
· Testing of tensile strength and biodegradation
· Toxicity test
In this blog, compared the generation of PHB in Cupriavidus necator fermentation using standard carbon source glucose and AW. Bacterial culture can be revived using nutrient broth. To maintain the stock and purity, TSA sub-culturing is done at regular intervals of 15 days.
Commercial polymer synthesis based on fermentation takes place in aerobic processes, therefore only approximately 50% of the primary carbon source has been utilized in the creation of biopolymers. The expenses of complex nitrogen sources are a second cost component in PHA's typical production procedures.
Through the use of a sodium hypochlorite digestion process, PHB can be recovered, and then the extracted PHB is dissolved in chloroform to create a biopolymer film. It was discovered that film is fragile and broke readily. Blending with CAB is done to address these problems. According to reports, CAB is a biodegradable, transparent thermoplastic that has received FDA approval. It is similar to cellulose acetate in strength but is more resistant to weathering and moisture absorption.
Abiotic factors and enzymatic degradation using PHB depolymerase and other degradation enzymes make up the overall degradation pathway. These enzymes use microbial invasion or microbial colonization to alter the internal molecular structure of biopolymers. As a result, biodegradation effectively starts at the surface and wraps around the inner molecular structure.
Plastic waste build-up in the environment compels manufacturers to create sustainable, biodegradable plastic. Biodegradation is a term that refers to biological activity.
The biodegradation of polymers consists of three important steps:
1. Biodeterioration, also known as the development of microorganisms on or inside the surface of the polymers, is the modification of the mechanical, chemical, and physical properties of the polymer.
2. Microorganisms can break down polymers into oligomers and monomers through a process called bio fragmentation.
3. Assimilation is a process in which microbes take the essential carbon, energy, and nutrients from fragmented polymers and use them to produce CO2, water, and biomass.
Chemical structure, polymer chain, crystallinity, and the complexity of the polymer formula are significant elements that influence how quickly plastics degrade in the environment. In actuality, enzymes choose and may digest specific functional groups. Polymers that have shorter chains, more amorphous parts, and simpler formulas are typically more prone to biodegradation by microbes. Additionally, the biodegradation of polymers is greatly influenced by the environment in which they are used or discarded. One of the most important environmental considerations for polymer biodegradation is the pH, temperature, moisture, and oxygen content.
Environmental issues have sparked more discussion and development in the bioplastics industry, broadening the selection of affordable biodegradable goods. Due to its numerous established advantages, such as preserving fossil fuels, reducing climate change, and generating employment in industries that are geared toward the future, bioplastics are now being treated seriously. Bioplastics are thought to be far more environmentally friendly than "non-renewable" conventional plastics because they come from a renewable source.
There are four types of degradable plastics:
1. Light-sensitive groups are added directly into the polymer's backbone in photodegradable bioplastics. prolonged ultraviolet exposure (a few weeks to months) might cause their polymeric structure to break down, leaving them vulnerable to additional bacterial deterioration
2. Bio-based bioplastics are described as "plastics in which 100% of the carbon is derived from renewable agricultural and forestry resources such as corn starch, soybean protein, and cellulose" by the Business-NGO (non-government organization) Working Group for Safer Chemicals and Sustainable Materials
3. Similar to other biodegradable materials, compostable bioplastics biologically degrade during the composting process without producing any obtrusive harmful waste. Standardized tests must be used to determine a plastic's overall biodegradability, degree of disintegration, and potential ecotoxicity of the degraded material in order to qualify it as biodegradable
4. Microorganisms completely break down biodegradable bioplastics without leaving any hazardous traces behind. In contrast to bio-based sustainable materials, the term "biodegradable" refers to substances that can naturally decompose or break down into biogases and biomass (mostly carbon dioxide and water) when exposed to a microbial environment and humidity, such as those found in soil. This reduces the amount of plastic waste generated. The fourth class of bioplastics is quite promising since microorganisms really utilize them.
In the current contemporary period, conventional plastic needs to be replaced with some superficial substitute that doesn't harm the environment in any way. Bioplastic should replace conventional plastic because it won't produce any harmful gases and can be broken down by microorganisms. Because conventional plastics don't degrade in the environment, incineration is used to break them down so as to cause as little harm to the environment's living things as possible. However, over time, incineration, recycling, and even manufacturing of conventional plastics produce some gases that are harmful to the environment. To overcome these problems, fermenters are needed for its production, and bioreactors can be used for its bulk breakdown. Amerging Technologies has invested all of its energy and resources into this battle.