Before we begin our discussion, let's understand How Biodegradable are Bioplastics?
Since there is often confusion when talking about bioplastics, let’s clarify some terms first.
Degradable – All plastic is degradable, even traditional plastic, but just because it can be broken down into tiny fragments or powder does not mean the materials will ever return to nature. Some additives to traditional plastics make them degrade more quickly. Photodegradable plastic breaks down more readily in sunlight; oxo-degradable plastic disintegrates more quickly when exposed to heat and light.
Biodegradable – Biodegradable plastic can be broken down completely into water, carbon dioxide and compost by microorganisms under the right conditions. “Biodegradable” implies that the decomposition happens in weeks to months. Bioplastics that don’t biodegrade that quickly are called “durable,” and some bioplastics made from biomass that cannot easily be broken down by microorganisms are considered non-biodegradable.
Compostable – Compostable plastic will biodegrade in a compost site. Microorganisms break it down into carbon dioxide, water, inorganic compounds and biomass at the same rate as other organic materials in the compost pile, leaving no toxic residue.
Types of Bioplastic
Bioplastics are currently used in disposable items like packaging, containers, straws, bags and bottles, and in non-disposable carpet, plastic piping, phone casings, 3D printing, car insulation and medical implants. The global bioplastic market is projected to grow from $17 billion this year to almost $44 billion in 2022.
There are two main types of bioplastics.
PLA (polylactic acid) is typically made from the sugars in corn starch, cassava or sugarcane. It is biodegradable, carbon-neutral and edible. To transform corn into plastic, corn kernels are immersed in sulfur dioxide and hot water, where its components break down into starch, protein, and fiber. The kernels are then ground and the corn oil is separated from the starch. The starch is comprised of long chains of carbon molecules, similar to the carbon chains in plastic from fossil fuels. Some citric acids are mixed in to form a long-chain polymer (a large molecule consisting of repeating smaller units) that is the building block for plastic. PLA can look and behave like polyethylene (used in plastic films, packing and bottles), polystyrene (Styrofoam and plastic cutlery) or polypropylene (packaging, auto parts, textiles).
PHA (polyhydroxyalkanoate) is made by microorganisms, sometimes genetically engineered, that produce plastic from organic materials. The microbes are deprived of nutrients like nitrogen, oxygen and phosphorus, but given high levels of carbon. They produce PHA as carbon reserves, which they store in granules until they have more of the other nutrients they need to grow and reproduce. Companies can then harvest the microbe-made PHA, which has a chemical structure similar to that of traditional plastics. Because it is biodegradable and will not harm living tissue, PHA is often used for medical applications such as sutures, slings, bone plates and skin substitutes; it is also used for single-use food packaging.
ZhuZhou China-based Green Star Biotechnology is one of the most famous companies producing PLA products under the brand name Green Star. Provides full biodegradable materials, PLA products and system solutions, founded by a team of experts and Doctors from the Bio-materials Research Center of well-known university in China.
They provide pla coated paper roll for making PLA paper cups, paper containers and also paper cutlary.(https://www.biogreenstar.com/Single-double-side-coated-paper/fully-biodegradable-singledouble-side-polylactic-lined-paper-eco-friendly-paper.) PLA based compostable bags, like trash bags, carry bags. (https://www.biogreenstar.com/Biodegradable-bags)
Bioplastics do produce significantly fewer greenhouse gas emissions than traditional plastics over their lifetime. There is no net increase in carbon dioxide when they break down because the plants that bioplastics are made from absorbed that same amount of carbon dioxide as they grew. A 2017 study determined that switching from traditional plastic to corn-based PLA would cut U.S. greenhouse gas emissions by 25 percent. The study also concluded that if traditional plastics were produced using renewable energy sources, greenhouse gas emissions could be reduced 50 to 75 percent; however, bioplastics that might in the future be produced with renewable energy showed the most promise for substantially reducing greenhouse gas emissions.