Region-Specific Sourcing of Lignocellulose Residues as Renewable Feedstocks for a Net-Zero Chemical Industry.

Biobased chemicals, crucial for the net-zero chemical industry, rely on lignocellulose residues as a major feedstock. However, its availability and environmental impacts vary greatly across regions. By 2050, we estimate that 3.0-5.2 Gt of these residues will be available from the global forest and agricultural sectors, with key contributions from Brazil, China, India, and the United States. This supply satisfies the growing global feedstock demands for plastics when used efficiently. Forest residues have 84% lower climate change impacts than agricultural residues on average globally but double the land-use-related biodiversity loss. Biobased plastics may reduce climate change impacts relative to fossil-based alternatives but are insufficient to fulfill net-zero targets. In addition, they pose greater challenges in terms of biodiversity loss and water stress. Avoiding feedstock sourcing from biodiversity-rich areas could halve lignocellulose residues-related biodiversity loss without significantly compromising availability. Improvements in region-specific feedstock sourcing, agricultural management and biomass utilization technologies are warranted for transitioning toward a sustainable chemical industry.

The degradation of single-use plastics and commercially viable bioplastics in the environment: A review.

Plastics have become an integral part of human life. Single-use plastics (SUPs) are disposable plastics designed to be used once then promptly discarded or recycled. This SUPs range from packaging and takeaway containers to disposable razors and hotel toiletries. Synthetic plastics, which are made of non-renewable petroleum and natural gas resources, require decades to perpetually disintegrate in nature thus contribute to plastic pollution worldwide, especially in marine environments. In response to these problems, bioplastics or bio-based and biodegradable polymers from renewable sources has been considered as an alternative. Understanding the mechanisms behind the degradation of conventional SUPs and biodegradability of their greener counterpart, bioplastics, is crucial for appropriate material selection in the future. This review aims to provide insights into the degradation or disintegration of conventional single-use plastics and the biodegradability of the different types of greener-counterparts, bioplastics, their mechanisms, and conditions. This review highlights on the biodegradation in the environments including composting systems. Here, the various types of alternative biodegradable polymers, such as bacterially biosynthesised bioplastics, natural fibre-reinforced plastics, starch-, cellulose-, lignin-, and soy-based polymers were explored. Review of past literature revealed that although bioplastics are relatively eco-friendly, their natural compositions and properties are inconsistent. Furthermore, the global plastic market for biodegradable plastics remains relatively small and require further research and commercialization efforts, especially considering the urgency of plastic and microplastic pollution as currently critical global issue. Biodegradable plastics have potential to replace conventional plastics as they show biodegradation ability under real environments, and thus intensive research on the various biodegradable plastics is needed to inform stakeholders and policy makers on the appropriate response to the gradually emerging biodegradable plastics.

Locust bean milling-derived dust as a raw material for the development of biodegradable bioplastics with antioxidant activity.

BACKGROUND: Non-value agrifood byproducts are rich in biomolecules such as proteins and polysaccharides, and possess film-forming ability, motivating their use in the development of biodegradable plastics. This work studied the feasibility of using locust bean milling-derived dust (LBMD) as a source of biomolecules suitable for developing biodegradable plastics. RESULTS: LBMD is composed of 56% protein, 28% carbohydrate, 10% moisture, 6% lipid, and 2% ash. In addition, phenolic compounds are also present. The carbohydrates are mainly composed by (1 → 4)-mannose, (1 → 4,6)-mannose, and t-galactose glycosidic linkages. Depending on the LBMD concentration used, when employed in casting biodegradable plastics, LBMD yields transparent yellowish bioplastics with 90% elongation at break and surface water contact angles ranging from 60° to 90°. Additionally, LBMD-based bioplastics display antioxidant activity, inhibiting cationic 2,2'-azino-bis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radicals up to 61% in just 24 h. LBMD-based bioplastics are disintegrated when incubated on the soil surface for 34 weeks, perhaps acting as a soil nutrient. CONCLUSION: LBMD represents a potential source of biomolecules for producing transparent, flexible, water tolerant, antioxidant, and biodegradable bioplastics, opening up opportunities to implement a novel circular strategy to valorize this locust bean industry byproduct. © 2022 Society of Chemical Industry.

Merging Plastics, Microbes, and Enzymes: Highlights from an International Workshop.

In the Anthropocene, plastic pollution is a worldwide concern that must be tackled from different viewpoints, bringing together different areas of science. Microbial transformation of polymers is a broad-spectrum research topic that has become a keystone in the circular economy of fossil-based and biobased plastics. To have an open discussion about these themes, experts in the synthesis of polymers and biodegradation of lignocellulose and plastics convened within the framework of The Transnational Network for Research and Innovation in Microbial Biodiversity, Enzymes Technology and Polymer Science (MENZYPOL-NET), which was recently created by early-stage scientists from Colombia and Germany. In this context, the international workshop "Microbial Synthesis and Degradation of Polymers: Toward a Sustainable Bioeconomy" was held on 27 September 2021 via Zoom. The workshop was divided into two sections, and questions were raised for discussion with panelists and expert guests. Several key points and relevant perspectives were delivered, mainly related to (i) the microbial evolution driven by plastic pollution; (ii) the relevance of and interplay between polymer structure/composition, enzymatic mechanisms, and assessment methods in plastic biodegradation; (iii) the recycling and valorization of plastic waste; (iv) engineered plastic-degrading enzymes; (v) the impact of (micro)plastics on environmental microbiomes; (vi) the isolation of plastic-degrading (PD) microbes and design of PD microbial consortia; and (vii) the synthesis and applications of biobased plastics. Finally, research priorities from these key points were identified within the microbial, enzyme, and polymer sciences.

Challenges and opportunities of biodegradable plastics: A mini review.

The concept of materials coming from nature with environmental advantages of being biodegradable and/or biobased (often referred to as bioplastics) is very attractive to the industry and to the consumers. Bioplastics already play an important role in the fields of packaging, agriculture, gastronomy, consumer electronics and automotive, but still they have a very low share in the total production of plastics (currently about 1% of the about 300 million tonnes of plastic produced annually). Biodegradable plastics are often perceived as the possible solution for the waste problem, but biodegradability is just an additional feature of the material to be exploited at the end of its life in specific terms, in the specific disposal environment and in a specific time, which is often forgotten. They should be used as a favoured choice for the applications that demand a cheap way to dispose of the item after it has fulfilled its job (e.g. for food packaging, agriculture or medical products). The mini-review presents the opportunities and future challenges of biodegradable plastics, regarding processing, properties and waste management options.

Biobased, biodegradable and compostable plastics: chemical nature, biodegradation pathways and environmental strategy.

Increasing pollution of plastic waste is one of the major global environmental threats, deteriorating our land, water and air. The shift towards biobased, biodegradable and compostable plastics is considered a green alternative to petroleum-based plastic due to its renewable source or biodegradability. However, there is a misconception about biodegradable plastics and their degradability and behaviour after service life. Biobased, biodegradable and compostable plastics offer various benefits such as less carbon footprint, energy efficiency, independence and eco-safety. On the other hand, there are some disadvantages such as higher cost, limited recycling, misuse of terms and lack of legislation. Also, there is an urgent need for comparable international standard methods to define these materials as biodegradable material, or biocompostable material. There are some standards currently available, however, an in-depth detail and explanation of these standards is still missing. This review outlines the basic definition and chemical structure of biobased, biodegradable and compostable plastics; describes the degradation pathways of biodegradable and compostable plastics; and summarises current key applications of these materials together with possible future applications in different industries. Finally, strategies are developed for minimising the environmental impacts and the need for future research is proposed.

Perceiving biobased plastics as an alternative and innovative solution to combat plastic pollution for a circular economy.

Plastic waste from fossil-based sources, including single-use packaging materials, is continuously accumulating in landfills, and leaching into the environment. A 2021 UN Environment Programme (UNEP) report suggests that the plastic pollution is likely to be doubled by 2030, posing a major challenge to the environment and the overall global plastic waste management efforts. The use of biobased plastics such as polyhydroxyalkanoates (PHAs) as a biodegradable substitute for petroleum-based plastics could be a feasible option to combat this issue which may further result in much lower carbon emissions and energy usage in comparison to conventional plastics as additional advantages. Though recent years have seen the use of microbes as biosynthetic machinery for biobased plastics, using various renewable feedstocks, the scaled-up production of such materials is still challenging. The current study outlays applications of biobased plastics, potential microorganisms producing biobased plastics such as Cupriavidus necator, Bacillus sp., Rhodopseudomonas palustris, microalgae, and mixed microbial cultures, and inexpensive and renewable resources as carbon substrates including industrial wastes. This review also provides deep insights into the operational parameters, challenges and mitigation, and future opportunities for maximizing the production of biobased plastic products. Finally, this review emphasizes the concept of biorefinery as a sustainable and innovative solution for biobased plastic production for achieving a circular bioeconomy.

Bioplastics on marine sandy shores: Effects on the key species Talitrus saltator (Montagu, 1808).

Talitrid amphipods are an important component of detritus web, playing a key role in the fragmentation of organic matters of marine and terrestrial origin, and it is well known that sandhoppers ingest microplastics. To assess the effective consumption of bioplastics and their effects on survival rate and on pollutants transfer (i.e. phthalates) on supralittoral arthropods, laboratory experiments were conducted by feeding adult T. saltator with two different types of bioplastic commonly used in the production of shopping bags. Groups of about 20 individuals were fed with 10 × 10 cm sample sheets of the two types of bioplastic for four weeks. The results show that amphipods ingest bioplastics even in the absence of microbial film and that ingestion of bioplastic can have effects on talitrid amphipods. Microtomographic analyses of faecal pellets seem consistent with this finding. The high phthalate concentrations in freshly collected individuals suggest the presence in the environment of these compounds, and the ability of amphipods to assimilate them, while the decrease in phthalate concentrations in bioplastic-fed individuals could be attributed to the scavenging effect of virgin plastic, as already observed in a previous study. In summary, the results indicate that different bioplastics may have effects on T. saltator (i.e. survival rate and faecal pellets structure) and confirm a potential role of amphipods in the degradation of bioplastics in supralittoral zone of marine sandy beaches, even when bioplastics are not colonized by bacterial biofilm that seems to improve palatability.

Designing Biobased Recyclable Polymers for Plastics.

Several concurrent developments are shaping the future of plastics. A transition to a sustainable plastics system requires not only a shift to fossil-free feedstock and energy to produce the carbon-neutral building blocks for polymers used in plastics, but also a rational design of the polymers with both desired material properties for functionality and features facilitating their recyclability. Biotechnology has an important role in producing polymer building blocks from renewable feedstocks, and also shows potential for recycling of polymers. Here, we present strategies for improving the performance and recyclability of the polymers, for enhancing degradability to monomers, and for improving chemical recyclability by designing polymers with different chemical functionalities.