(Jorge Vidal/Rice University)
The race is on to find practical substitutes for the petroleum-based plastics our societies have become so dependent on, and materials scientists from Rice University have a new lead. Their bacteria-produced biomaterial, BCBN (bacterial cellulose-hexagonal boron nitride), transforms what is naturally a random arrangement of bacterial cellulose fibers by rotating the microbes as they grow inside a bioreactor…….Continue reading…..
By: Jess Cockerill
Source: ScienceAlert
.
Critics:
Materials such as starch, cellulose, wood, sugar and biomass are used as a substitute for fossil fuel resources to produce bioplastics; this makes the production of bioplastics a more sustainable activity compared to conventional plastic production. The environmental impact of bioplastics is often debated, as there are many different metrics for “greenness” (e.g., water use, energy use, deforestation, biodegradation, etc.).
Hence bioplastic environmental impacts are categorized into nonrenewable energy use, climate change, eutrophication and acidification. Bioplastic production significantly reduces greenhouse gas emissions and decreases non-renewable energy consumption. Firms worldwide would also be able to increase the environmental sustainability of their products by using bioplastics.
Although bioplastics save more nonrenewable energy than conventional plastics and emit less greenhouse gasses compared to conventional plastics, bioplastics also have negative environmental impacts such as eutrophication and acidification. Bioplastics induce higher eutrophication potentials than conventional plastics. Biomass production during industrial farming practices causes nitrate and phosphate to filtrate into water bodies; this causes eutrophication, the process in which a body of water gains excessive richness of nutrients.
Eutrophication is a threat to water resources around the world since it causes harmful algal blooms that create oxygen dead zones, killing aquatic animals. Bioplastics also increase acidification. The high increase in eutrophication and acidification caused by bioplastics is also caused by using chemical fertilizer in the cultivation of renewable raw materials to produce bioplastics. Other environmental impacts of bioplastics include exerting lower human and terrestrial ecotoxicity and carcinogenic potentials compared to conventional plastics.
However, bioplastics exert higher aquatic ecotoxicity than conventional materials. Bioplastics and other bio-based materials increase stratospheric ozone depletion compared to conventional plastics; this is a result of nitrous oxide emissions during fertilizer application during industrial farming for biomass production. Artificial fertilizers increase nitrous oxide emissions especially when the crop does not need all the nitrogen. Minor environmental impacts of bioplastics include toxicity through using pesticides on the crops used to make bioplastics.
Bioplastics also cause carbon dioxide emissions from harvesting vehicles. Other minor environmental impacts include high water consumption for biomass cultivation, soil erosion, soil carbon losses and loss of biodiversity, and they are mainly are a result of land use associated with bioplastics. Land use for bioplastics production leads to lost carbon sequestration and increases the carbon costs while diverting land from its existing uses.
Although bioplastics are extremely advantageous because they reduce non-renewable consumption and GHG emissions, they also negatively affect the environment through land and water consumption, using pesticide and fertilizer, eutrophication and acidification; hence one’s preference for either bioplastics or conventional plastics depends on what one considers the most important environmental impact.
Another issue with bioplastics, is that some bioplastics are made from the edible parts of crops. This makes the bioplastics compete with food production because the crops that produce bioplastics can also be used to feed people. These bioplastics are called “1st generation feedstock bioplastics”. 2nd generation feedstock bioplastics use non-food crops (cellulosic feedstock) or waste materials from 1st generation feedstock (e.g. waste vegetable oil). Third generation feedstock bioplastics use algae as the feedstock.
The concept of bioplastics dates back to the early 20th century. However, significant advancements occurred in the 1980s and 1990s when researchers began developing biodegradable plastics from natural sources. The construction industry started to take notice of bioplastics’ potential in the late 2000s, driven by the global push for greener building practices.
In recent years, bioplastics have seen considerable advancements in terms of durability, cost-effectiveness, and performance. Innovations in biopolymer blends and composites have made bioplastics more suitable for construction applications, ranging from insulation to structural components. While plastics based on organic materials were manufactured by chemical companies throughout the 20th century, the first company solely focused on bioplastics—Marlborough Biopolymers—was founded in 1983.
However, Marlborough and other ventures that followed failed to find commercial success, with the first such company to secure long-term financial success being the Italian company Novamont, founded in 1989. Bioplastics remain less than one percent of all plastics manufactured worldwide. Most bioplastics do not yet save more carbon emissions than are required to manufacture them.
It is estimated that replacing 250 million tons of the plastic manufactured each year with bio-based plastics would require 100 million hectares of land, or 7 percent of the arable land on Earth. And when bioplastics reach the end of their life cycle, those designed to be compostable and marketed as biodegradable are often sent to landfills due to the lack of proper composting facilities or waste sorting, where they then release methane as they break down anaerobically.
Leave a Reply