Twisting biomaterials around your little finger: environmental impacts of bio-based wrappings

Background, aim, and scope  

Packaging uses nearly 40% of all polymers, a substantial share of which is used for sensitive merchandise such as moisture-sensitive food. To find out if bio-based materials are environmentally advantageous for this demanding application, we compared laminated, printed film across the whole life cycle.     

Environmental impacts of conventional plastic and bio-based carrier bags

Background, aim, and scope  

Worldwide, the production of biodegradable and compostable plastics has steadily grown. In Part 1 (Khoo et al. 2010), life cycle assessment (LCA) was applied to compare the production stages of a bio-based bag (made from polyhydroxyalkanoate or bio-plastic (PHA)) with polyethylene plastic bag. The scope of the study is within the context of Singapore and does not include other types of conventional or bio-based polymers (e.g., polylactic acid (PLA), thermoplastics, high-density polyethylene (HDPE), EPS, etc). This article (part 2) proposes to investigate the end-of-life options of both bags.     

国内生物基材料产业发展现状

近年来,生物基材料正逐步成为引领当代世界科技创新和经济发展的又一新的主导产业。文章综述了国内生物基材料产业的最新进展,对整个生物基材料产业市场进行了综合分析,包括生物基化学品如乳酸、1,3-丙二醇、丁二酸等,可生物降解生物基塑料如二元酸二元醇共聚酯、聚乳酸、二氧化碳共聚物、聚羟基烷酸酯、聚己内酯、热塑性生物质塑料,非生物降解生物基塑料如生物基聚酰胺、聚对苯二甲酸丙二醇酯、生物基聚氨酯,以及生物基纤维等材料的产业现状。     

Life cycle assessment of single use thermoform boxes made from polystyrene (PS), polylactic acid, (PLA), and PLA/starch: cradle to consumer gate

Purpose

Currently, the bio-based plastics have been drawing considerable attention from the packaging industry as a sustainable solution for replacing petroleum-based plastics in order to reduce the accumulation of plastic waste in the environment. This work has benchmarked the environmental impact of bio-based against petroleum-based plastics for single use boxes. In this paper, the cradle to consumer gate environmental impact data of these boxes was calculated and reported as part 1. End-of-life options of both bio- and petroleum-based boxes are an important subject which will be further studied for part 2. The energy sources in this work were taken from the Thailand energy database namely: Thai electricity grid mix (TEGM), Thai coal electricity (TCE), Thai natural gas combine cycle (TNGCC), and Thai coal integrated gasification combine cycle (TIGCC).

Methods

The materials studied were polystyrene (PS) derived from petroleum, polylactic acid (PLA) derived from corn, and PLA/cassava starch blend (PLA/starch). The tray with lid (herein after called box) was processed in a plastic manufacturing in Thailand using cast sheet extrusion and then thermoforming techniques. The functional unit is specified as 10,000 units of 8.0?×?10.0?×?2.5 cm of PS, PLA, and PLA/starch boxes which weigh 447.60, 597.60, and 549.56 kg, respectively. Three impact categories; namely global warming potential including direct greenhouse gas, and indirect land use change (LUC) emissions, acidification, and photochemical ozone formation are investigated. Finally, the normalization results including and excluding LUC consideration were compared and reported.

Results and discussion

The results from this study have shown that the total environmental impact including LUC emission of bio-based boxes were different when the various energy sources were supplied throughout the life cycle production stage. It can be seen that the PS box has lower environmental impact than PLA and PLA/starch boxes when TEGM, TCE, TNGCC, and TIGCC were used as energy supplied. LUC of renewable feedstocks, such as corn and cassava, were considered as the biggest impact of absolute scores of PLA and PLA/starch boxes. These results are consistent with Piemonte and Gironi (2010).

Conclusions

PLA and PLA/starch boxes give a slightly higher environmental impact than the PS box by 1.59 and 1.09 times, respectively, when LUC was not accounted in the absolute scores and clean energy TIGCC was used throughout the life cycle.     

Marlo’s windows: why it is a mistake to ignore hazard resistance in LCA

Purpose

Hazard-resistant materials for homes promise environmental benefits, such as avoided waste and materials for repairs, which can be overlooked by scoping in life-cycle assessment (LCA) approaches. Our motivation for pursuing this research was to see how incorporating these avoided losses in the LCA could impact choices between hazard-resistant and traditional materials.

Methods

Two choices common in home construction were analyzed using an LCA process that incorporates catastrophe modeling to consider avoided losses made possible with hazard-resistant materials. These findings were compared to those based on a similar LCA that did not consider these avoided losses. The choices considered were standard windows vs. windows with impact-resistant glass and standard windows with no opening protection vs. standard windows with impact-resistant storm panels.

Results and discussion

For the window comparisons, the standard products were environmentally preferable when avoided losses from storm events were not considered in the LCA. However, when avoided losses were considered, the hazard-resistant products were environmentally preferable. Considering avoided losses in LCAs, as illustrated by the window choices, can change which product appears to be the environmentally preferable option. Further, as home service life increases, the environmental net benefit of the hazard-resistant product increases.

Conclusions

Our results show the value of an LCA approach which allows more complete scopings of comparisons between hazard-resistant materials and their traditional counterparts. This approach will help translate the impacts of hazard-resistant products into the more familiar language used to talk about “green” products, enabling more informed decisions by product manufacturers, those who develop building certification systems and codes, researchers, and other building industry stakeholders.     

聚乳酸塑料合成、生物降解及其废弃物处置的研究进展

随着国内外禁塑令和限塑令的升级,以聚乳酸(polylactic acid, PLA)为代表的生物基塑料成为传统石油基塑料市场的主要替代品,备受产业界的青睐。然而,公众对生物基塑料的认识仍存在诸多误解。事实上,生物基塑料的降解需要在特定条件下才能实现,泄入到自然环境中同样难以降解,会对人体、生物多样性和生态系统功能造成危害,这与传统石油基塑料相似。近年来,随着我国PLA产能和市场规模不断的提高,亟需进一步加强对PLA等生物基塑料降解性能的认识,挖掘PLA生物降解资源,关注和研究生物基塑料回收处理模式。基于上述背景,本文首先介绍了PLA塑料的性质及合成方式,以及PLA塑料的产业化与市场规模;其次,对目前聚乳酸塑料微生物与酶法降解的研究进展进行了综述,并对其生物降解机制进行了探讨;最后,提出了微生物原位处理和酶法闭环回收两种聚乳酸塑料废弃物生物处置方法,并对PLA生物基塑料的发展前景和趋势进行了展望。     

Production of functionalized polyhydroxyalkanoates by genetically modified <Emphasis Type="Italic">Methylobacterium extorquens</Emphasis> strains

Background  

Methylotrophic (methanol-utilizing) bacteria offer great potential as cell factories in the production of numerous products from biomass-derived methanol. Bio-methanol is essentially a non-food substrate, an advantage over sugar-utilizing cell factories. Low-value products as well as fine chemicals and advanced materials are envisageable from methanol. For example, several methylotrophic bacteria, including Methylobacterium extorquens, can produce large quantities of the biodegradable polyester polyhydroxybutyric acid (PHB), the best known polyhydroxyalkanoate (PHA). With the purpose of producing second-generation PHAs with increased value, we have explored the feasibility of using M. extorquens for producing functionalized PHAs containing C-C double bonds, thus, making them amenable to future chemical/biochemical modifications for high value applications.     

Recent advances in polysaccharide bio-based flocculants

Natural polysaccharides, derived from biomass feedstocks, marine resources, and microorganisms, have been attracting considerable attention as benign and environmentally friendly substitutes for synthetic polymeric products. Besides many other applications, these biopolymers are rapidly emerging as viable alternatives to harmful synthetic flocculating agents for the removal of contaminants from water and wastewater. In recent years, a great deal of effort has been devoted to improve the production and performance of polysaccharide bio-based flocculants. In this review, current trends in preparation and chemical modification of polysaccharide bio-based flocculants and their flocculation performance are discussed. Aspects including mechanisms of flocculation, biosynthesis, classification, purification and characterization, chemical modification, the effect of physicochemical factors on flocculating activity, and recent applications of polysaccharide bio-based flocculants are summarized and presented.     

Lipase-catalysed acylation of starch and determination of the degree of substitution by methanolysis and GC

Background  

Natural polysaccharides such as starch are becoming increasingly interesting as renewable starting materials for the synthesis of biodegradable polymers using chemical or enzymatic methods. Given the complexity of polysaccharides, the analysis of reaction products is challenging.     

Expression of the entire polyhydroxybutyrate operon of <Emphasis Type="Italic">Ralstonia eutropha</Emphasis> in plants

Background

Previously we demonstrated that an entire bacterial operon (the PRN operon) is expressible in plants when driven by the Tomato -yellow-leaf-curl-virus (TYLCV) -derived universal vector IL-60.Petroleum-derived plastics are not degradable, and are therefore harmful to the environment. Fermentation of bacteria carrying operons for polyhydroxyalkanoates (PHAs) produces degradable bioplastics which are environmentally friendly. However, bacterial production of bioplastics is not cost-effective, and attention is turning to their production in plants. Such “green” plastics would be less expensive and environmentally friendly. Hence, attempts are being made to substitute petroleum-derived plastics with “green” plastics. However, transformation of plants with genes of operons producing bioplastics has deleterious effects. Transformation of plastids does not cause deleterious effects, however it is a complicated procedures.

Results

We have developed another TYLCV-based vector (SE100) and show that yet another bacterial operon (the phaCAB operon) when driven by SE100 is also expressed in plants. We employed the combination of SE100 and the phaCAB operon to drive the operon to the plastids and produce in plants a biodegradable plastic [polyhydroxybutyrate (PHB)].Here we indicate that the bacterial operon (phaCAB), when driven by the newly developed universal plant vector SE100 is directed to chloroplasts and produces in plants PHB, a leading PHA. The PHB-producing plants circumvent the need for complicated technical procedures.

Conclusion

The viral vector system SE100 facilitated the production of the bio-plastic poly-3-hydroxybutyrate. This was achieved by using the full pha-CAB operon indicating that TYLCV based system can transcribe and translate genes from bacterial operons controlled by a single cis element. Our data hints to the participation of the chloroplasts in these processes.

     

Life cycle assessment of bio-based ethanol produced from different agricultural feedstocks

Purpose

Bio-based products are often considered sustainable due to their renewable nature. However, the environmental performance of products needs to be assessed considering a life cycle perspective to get a complete picture of potential benefits and trade-offs. We present a life cycle assessment of the global commodity ethanol, produced from different feedstock and geographical origin. The aim is to understand the main drivers for environmental impacts in the production of bio-based ethanol as well as its relative performance compared to a fossil-based alternative.

Methods

Ethanol production is assessed from cradle to gate; furthermore, end-of-life emissions are also included in order to allow a full comparison of greenhouse gas (GHG) emissions, assuming degradation of ethanol once emitted to air from household and personal care products. The functional unit is 1 kg ethanol, produced from maize grain in USA, maize stover in USA, sugarcane in North-East of Brazil and Centre-South of Brazil, and sugar beet and wheat in France. As a reference, ethanol produced from fossil ethylene in Western Europe is used. Six impact categories from the ReCiPe assessment method are considered, along with seven novel impact categories on biodiversity and ecosystem services (BES).

Results and discussion

GHG emissions per kilogram bio-based ethanol range from 0.7 to 1.5 kg CO₂ eq per kg ethanol and from 1.3 to 2 kg per kg if emissions at end-of-life are included. Fossil-based ethanol involves GHG emissions of 1.3 kg CO₂ eq per kg from cradle-to-gate and 3.7 kg CO₂ eq per kg if end-of-life is included. Maize stover in USA and sugar beet in France have the lowest impact from a GHG perspective, although when other impact categories are considered trade-offs are encountered. BES impact indicators show a clear preference for fossil-based ethanol. The sensitivity analyses showed how certain methodological choices (allocation rules, land use change accounting, land use biomes), as well as some scenario choices (sugarcane harvest method, maize drying) affect the environmental performance of bio-based ethanol. Also, the uncertainty assessment showed that results for the bio-based alternatives often overlap, making it difficult to tell whether they are significantly different.

Conclusions

Bio-based ethanol appears as a preferable option from a GHG perspective, but when other impacts are considered, especially those related to land use, fossil-based ethanol is preferable. A key methodological aspect that remains to be harmonised is the quantification of land use change, which has an outstanding influence in the results, especially on GHG emissions.     

A micro-fluidic study of whole blood behaviour on PMMA topographical nanostructures

Background  

Polymers are attractive materials for both biomedical engineering and cardiovascular applications. Although nano-topography has been found to influence cell behaviour, no established method exists to understand and evaluate the effects of nano-topography on polymer-blood interaction.     

Biodegradable and compostable alternatives to conventional plastics

Packaging waste forms a significant part of municipal solid waste and has caused increasing environmental concerns, resulting in a strengthening of various regulations aimed at reducing the amounts generated. Among other materials, a wide range of oil-based polymers is currently used in packaging applications. These are virtually all non-biodegradable, and some are difficult to recycle or reuse due to being complex composites having varying levels of contamination. Recently, significant progress has been made in the development of biodegradable plastics, largely from renewable natural resources, to produce biodegradable materials with similar functionality to that of oil-based polymers. The expansion in these bio-based materials has several potential benefits for greenhouse gas balances and other environmental impacts over whole life cycles and in the use of renewable, rather than finite resources. It is intended that use of biodegradable materials will contribute to sustainability and reduction in the environmental impact associated with disposal of oil-based polymers.The diversity of biodegradable materials and their varying properties makes it difficult to make simple, generic assessments such as biodegradable products are all ‘good’ or petrochemical-based products are all ‘bad’. This paper discusses the potential impacts of biodegradable packaging materials and their waste management, particularly via composting. It presents the key issues that inform judgements of the benefits these materials have in relation to conventional, petrochemical-based counterparts. Specific examples are given from new research on biodegradability in simulated ‘home’ composting systems. It is the view of the authors that biodegradable packaging materials are most suitable for single-use disposable applications where the post-consumer waste can be locally composted.     

Twin Screw Extruders as Continuous Mixers for Thermal Processing: a Technical and Historical Perspective

Developed approximately 100 years ago for natural rubber/plastics applications, processes via twin screw extrusion (TSE) now generate some of the most cutting-edge drug delivery systems available. After 25 or so years of usage in pharmaceutical environments, it has become evident why TSE processing offers significant advantages as compared to other manufacturing techniques. The well-characterized nature of the TSE process lends itself to ease of scale-up and process optimization while also affording the benefits of continuous manufacturing. Interestingly, the evolution of twin screw extrusion for pharmaceutical products has followed a similar path as previously trodden by plastics processing pioneers. Almost every plastic has been processed at some stage in the manufacturing train on a twin screw extruder, which is utilized to mix materials together to impart desired properties into a final part. The evolution of processing via TSEs since the early/mid 1900s is recounted for plastics and also for pharmaceuticals from the late 1980s until today. The similarities are apparent. The basic theory and development of continuous mixing via corotating and counterrotating TSEs for plastics and drug is also described. The similarities between plastics and pharmaceutical applications are striking. The superior mixing characteristics inherent with a TSE have allowed this device to dominate other continuous mixers and spurred intensive development efforts and experimentation that spawned highly engineered formulations for the commodity and high-tech plastic products we use every day. Today, twin screw extrusion is a battle hardened, well-proven, manufacturing process that has been validated in 24-h/day industrial settings. The same thing is happening today with new extrusion technologies being applied to advanced drug delivery systems to facilitate commodity, targeted, and alternative delivery systems. It seems that the “extrusion evolution” will continue for wide-ranging pharmaceutical products.     

Avidin related protein 2 shows unique structural and functional features among the avidin protein family

Background  

The chicken avidin gene family consists of avidin and several avidin related genes (AVRs). Of these gene products, avidin is the best characterized and is known for its extremely high affinity for D-biotin, a property that is utilized in numerous modern life science applications. Recently, the AVR genes have been expressed as recombinant proteins, which have shown different biotin-binding properties as compared to avidin.     

Sustainable synthesis and applications of polyhydroxyalkanoates (PHAs) from biomass

Polyhydroxyalkanoates (PHAs) belong to group of biopolymers that have in recent times received growing research interest as a result of being eco-friendly and close characteristics with petrochemical based plastics. Alternatives to utilization of synthetic plastics are being explored since synthetic plastics are non-recyclable and non-biodegradable in nature. One of the innovations of Green Chemistry is utilization of renewable feedstocks such as biomass to achieve sustainable development with future circular economy. Bio-based products are of great interest to sustainable development as a result of diminishing fossil fuel reserves and rising environmental concerns. This review summarizes the productions of PHAs from renewable feedstocks such as lignocellulose, crude glycerol, levulinic acid (LA), palm-oil mill effluents (POME) and waste oils. The production of bio-based polymers has become much more professional and differentiated in recent years. Presently, there are bio-based alternatives for practically every application, therefore, this review presents applications of PHA in bio-refinery, medical sectors, agriculture sector, construction industry, and in packaging industry. The cost analysis of PHA from renewable sources with commercially available ones and potential to attain circular economy were also stressed. The reasons for this shift are connected to the non-renewability of fossil-based resources, the deteriorating environmental impacts, and the lack of biodegradability of the petroleum-produced materials.     

BglBricks: A flexible standard for biological part assembly

Background  

Standard biological parts, such as BioBricks™ parts, provide the foundation for a new engineering discipline that enables the design and construction of synthetic biological systems with a variety of applications in bioenergy, new materials, therapeutics, and environmental remediation. Although the original BioBricks™ assembly standard has found widespread use, it has several shortcomings that limit its range of potential applications. In particular, the system is not suitable for the construction of protein fusions due to an unfavorable scar sequence that encodes an in-frame stop codon.     

Using life cycle thinking to analyze environmental labeling: the case of appearance wood products

Purpose

Growing public concern about the current state of our planet led to the creation of numerous regulations, standards, and certifications for the protection of humans and the environment. Ecolabels were defined for products such as cleaning products, paints, and many others. Wood building products are no exception. The objective of this study is to analyze the existing ecolabelling programs for appearance wood products in nonresidential applications and to evaluate them relatively to their effective role in environment protection or reduction of environment footprint.

Methods

The research was conducted on the most common International Organization for Standardization (ISO) type I ecolabels in North America, the European Union, and Japan. Certification schemes applicable to appearance wood products for nonresidential applications were considered. In a life cycle assessment perspective, certification criteria were compared regarding their ability to consider and integrate environment impacts.

Results and discussion

A wide range of ecolabels can apply to appearance wood products, from indoor air quality to wood from sustainable forest management. Moreover, it has been found that among all certification schemes studied, those integrating the whole life cycle were the most relevant.

Conclusions

The remaining limitation of ISO type I ecolabels is the lack of environmental information enabling the differentiation between products bearing the same ecolabel. This can be overcome by ISO type III environmental product declarations. Thus, allowing a better understanding of the implications related with the use of wood products compared to other materials in the nonresidential building sector.     

A study on the environmental aspects of WEEE plastic recycling in a Brazilian company

Purpose

The high consumption of electrical and electronic equipment motivated by the rapid technological advances seen over the years has lead to an increase in the generation of waste electrical and electronic equipment (WEEE). Such residues contain various dangerous substances and therefore deserve special attention. To that end, the Brazilian Policy on Solid Waste has provided guidelines on integrated and solid waste management, such as consumer electronics, aiming at their appropriate disposal and treatment through reverse logistics. In this context, the present work focuses on studying the recycling of some WEEE plastics.

Methods

This study was conducted using the methodological framework presented in the International Standard ISO 14040:2006 and aimed to determine the life cycle inventory (LCI) of a WEEE plastic recycling process in a company in Brazil. Having collected the data, it was possible to identify and quantify the environmental aspects caused by the recycling process of major plastics (acrylonitrile-butadiene-styrene (ABS) and high impact polystyrene (HIPS). The study was conducted in the only company in Brazil that operates WEEE plastic recycling in large scale.

Results and discussion

Some of the environmental aspects caused during the recycling process of the plastics under study were identified and quantified. As a result, besides presenting the inventory, it was also possible to determine a reduction in the consumption of energy and in CO₂ emissions. When compared to the production of virgin ABS and HIPS, the recycling processes for such plastics showed a reduction in energy consumption by approximately 90% for both plastics and a reduction in CO₂ emissions by approximately 84% for HIPS and 87% for ABS. The plastics recycled by the company retain over 90% of their virgin mechanical properties.

Conclusions

The study shows that recycling is highly relevant and that components present in WEEE received appropriate destination and treatment. Recycling avoids environmental impacts as it prevents WEEE from being disposed of in landfills and as the pellets of recycled plastics can re-enter the supply chain as raw materials. Considering the legislation in Brazil, the stage of collection/transport/treatment of WEEE conducted by the company under study presents strong indications of contributions to the environment, society, and economy of the country.

     

Life cycle assessment of bio-based products: a disposable diaper case study

Purpose

In this study, a life cycle assessment of a bioplastic based diaper was performed. The product has several innovative elements, due to the implementation of eco-design principles, such as: (1) introduction of biopolymers (namely polylactic acid (PLA) and Mater-bi®), (2) relevant reduction of petrochemical plastics, and (3) minimization of energy consumptions and use of renewable energy in manufacturing. The aim of the study is to evaluate the environmental benefits gained through eco-innovation, while identifying further areas of improvement.

Methods

The bio-based diaper has been evaluated using a “cradle-to-gate” analysis. The functional unit is one diaper, assuming an average size among the different commercial options. A case study of an enterprise in Italy (WIP S.p.A) was carried out to collect as much reliable primary data as possible. In order to highlight potential areas of improvement and to compare the environmental performance of the product, a sensitivity analysis based on three different impact assessment methods (adopting ReCiPe 2008, IMPACT 2002+ and Cumulative Energy Demand (CED)) and a comparison with a standard commercial diaper were performed. Finally, three possible end-of-life scenarios including composting of WIP diaper were hypothesized and tested.

Results and discussion

Contribution analysis suggested that sourcing and production of raw materials used in WIP diaper manufacturing contributed most significantly to the potential environmental impacts. Adopting ReCiPe method, pulp, and sodium polyacrylate present the highest environmental burdens in WIP diaper system. Applying IMPACT2002+ method, PLA relative contribution to the toxicity increases, due to the generation of the electricity used in corn production and in PLA production phases. For both methods, impacts related to energy consumption of the WIP diapers’ production process look to be negligible. WIP diaper performance has room for improvement, since critical points were detected in the life cycle stages of raw materials used. However, the results of the normalization step, according to ReCiPe method, state that WIP diapers can bring environmental benefits, compared to standard ones. Moreover, if composting end-of-life scenario is included in the assessment, there is a significant improvement in WIP diaper environmental performance compared to a standard diaper.

Conclusions

Integrating eco-innovation and eco-design principles in the production of the bio-based diaper leads to a better environmental profile, compared to the standard one. Nevertheless, there are several areas of concerns to be considered in order to further improve its environmental performance. So far, the possible improvements identified from the case study are: (1) the selection of biopolymers suppliers with better production systems from an environmental point of view, (2) the reduction of distances along the supply chain, and (3) the implementation of composting procedures for the end of life. In conclusion, the introduction of biopolymers in diaper composition could lead them to be preferable compared to standard diapers, but criticisms arise, which need to be solved, to avoid the risk of burdens shifting.