Second-generation Feedstocks Research Articles

Comparative life cycle assessment of PBAT from fossil-based and second-generation generation bio-based feedstocks

With the increasing demand for plastics, plastic pollution is growing rapidly. A significant amount of plastic has leaked into the environment, leading to severe environmental issues. Biodegradable plastics are considered promising alternatives to conventional durable plastics, and the environmental impacts of biodegradable plastics have received increasing attention. Poly (butylene adipate-co-terephthalate) (PBAT) is a commercial and cost-competitive biodegradable polymer and has been applied in the packaging and agriculture sectors. The environmental performances of PBAT with second-generation feedstocks from forestry waste have been rarely investigated. Since China is the leading global producer and exporter of PBAT polymer, Chinese cradle-to-gate life cycle inventories of PBAT were compiled in this study. A comparative life cycle assessment (LCA) was conducted to explore the potential for environmental performance of PBAT with second-generation bio-based feedstock compared to fossil-based PBAT and conventional plastics. The results showed that feedstocks contributed to more than 70 % of 18 environmental impact categories of fossil-based PBAT. In comparison, PBAT with second-generation bio-based feedstock reduces the environmental loads in 16 impact categories by 15–85 %, and renewable energy substitution has the potential to reduce environmental impacts by 10 %. Bio-based PBAT performs better than PVC, PP, HDPE, LDPE, and PET in 16 impact categories by 15–80 %. Bio-based PBAT has GWP of 3.72 kg CO2 eq, which is 37 % lower than fossil-based PBAT (5.89 kg CO2 eq) and 18–32 % lower than conventional plastics. Since feedstock dominates the environmental performance of PBAT, the development of biomanufacturing technologies for bio-based polymers and chemicals could significantly improve environmental performance of biodegradable plastics and promote the sustainable development of the plastic industry. Results could serve as the basis for environmental impact and mitigation strategies for biodegradable plastics with bio-based feedstocks, as well as the sustainable development of the PBAT industry.

Escherichia coli-based biorefining process yields optically pure lactic acid from fermented second-generation feedstocks

Within the circular bioeconomy the production of optically pure LA from 2nd generation feedstocks would be ideal but it is very challenging. In this paper genetically engineered Escherichia coli strains were created to resolve racemic LA solutions synthesised and produced from the fermentation of organic waste or ensiled grass. Refining LA racemic mixtures into either a D- or L-LA was achieved by cells being able to consume one LA isomer as a sole carbon and energy source while not being able to consume the other. A D-LA refining strain JSP0005 was grown on fermented source-sorted organic household waste and different grass silage leachates, which are 2nd generation feedstocks containing up to 33 g/L lactic acid racemate. In all growth experiments, L-LA was completely removed leaving D-LA as the only LA stereoisomer, i.e. resulting in optically pure D-LA, which also increased by as much as 248.6 % from its starting concentration, corresponding to 38 g/L. The strains resulting from this study are a promising first step towards a microbial based LA biorefining process.

Study of Lipid Accumulation from Chlorococcum Microalga for Biodiesel Conversion

Microalgae-derived biodiesel seems to be a viable substitute for petroleum-based transportation fuels as a renewable biofuel. Raising the lipid content of microalgal strains may therefore provide a low-cost second-generation feedstock for the synthesis of biodiesel. Chlorococcum growth and lipid accumulation were investigated under a range of culture conditions, including CO2 concentration, temperature, and nitrate concentrations. The lipid content increased significantly by 33.1 ± 0.28% of dry cell weight in N-/30 ºC/CO2 cultivation in Bristol medium. The highest biomass productivity was achieved at 30ºC when there was adequate nitrogen and CO2 supplementation (N+/30 oC/CO2). Gas chromatography was employed to determine the proper ratio of fatty acids. The biomass of chlorococcum shows great potential as a feedstock for the manufacture of biodiesel since it is mostly composed of oleic and linoleic fatty acids.

SOYBEAN AND WASTE COOKING OIL BASED FEEDSTOCKS AS A SUSTAINABLE BIOFUEL

Fuel in transportation is necessary and gas release from transportation activity raises concern of pollution. Sustainable fuels sources are from biomass can convert to the alternative to the bioenergy fuel. It is actively investigated with concern in the environmental effects if using conventional fuels from reservoir of fossil fuels. Hence, to counter these consequences, Sustainable Fuels (SF) is investigated as it is considered a renewable source of fuel. Thus, this study aims to establish an experiment to determine the suitability of biomass fuel by using soybean and waste cooking oil feedstocks. An experiment is set up to produce biomass fuel by using feedstock from different biomass particularly from soybean oil, a first-generation edible feedstock and waste cooking oil, a second-generation nonedible feedstock. The method chosen to produce biomass fuel is transesterification. The experiment will test the effects of a catalyst, namely solid Potassium Hydroxide, KOH, with three levels of concentration 0.75%, 1%, and 1.5% w/w KOH. Once the biomass fuel is produced it will undergo a series of tests to study the effect of parameters such as density, kinematic viscosity, caloric value, acid value and Fatty Acid Methyl Ester (FAME). The results show that using the feedstock 0.75 w/w% of KOH, the yield of biomass fuel is the most for both feedstocks. It is noted that soybean oil yields slightly greater feedstock than waste cooking oil. The density for both feedstock is very similar at 0.87-0.88 g/cm3. The acid value of biomass fuel produced from waste cooking oil is much higher than soybean oil at 0.28 but still under the acceptance range of 0.5. The concentration of catalyst used is a major factor in the yield of biomass fuel. It is also noted that the first-generation edible feedstock of soybean oil produces greater quality of biomass fuel. Nevertheless, first-generation feedstock still poses the food competition threat in comparison to second-generation feedstock. Therefore, establishment of the second-generation feedstock from waste cooking oil produces biomass fuel that is close to the quality of soybean oil, it is a more preferred feedstock compared to soybean oil.

Addressing raw material variability: In-line FTIR sugar composition analysis of lignocellulosic process streams

For a sustainable economy, biorefineries that use second-generation feedstocks to produce biochemicals and biofuels are essential. However, the exact composition of renewable feedstocks depends on the natural raw materials used and is therefore highly variable. In this contribution, a process analytical technique (PAT) strategy for determining the sugar composition of lignocellulosic process streams in real-time to enable better control of bioprocesses is presented. An in-line mid-IR probe was used to acquire spectra of ultra-filtered spent sulfite liquor (UF-SSL). Independent partial least squares models were developed for the most abundant sugars in the UF-SSL. Up to 5 sugars were quantified simultaneously to determine the sugar concentration and composition of the UF-SSL. The lowest root mean square errors of the predicted values obtained per analyte were 1.02 g/L arabinose, 1.25 g/L galactose, 0.50 g/L glucose, 1.60 g/L mannose, and 0.85 g/L xylose. Equipped with this novel PAT tool, new bioprocessing strategies can be developed for UF-SSL.

Purification of lipid oil using ion exchange resins

AbstractOil upgrading technologies for fuel production from second-generation feedstocks require pretreatments, such as the removal of ash metals in crude oil, to improve the catalytic performance in the process. The aim of this work was to purify lipid crude oil, derived from black soldier fly larvae (BSFL), from calcium by dry washing using ion exchange resins. Commercially available ion exchange resins suitable for organic liquids, namely GF 202 and Amberlyst 15DRY (AL 15), were selected for the purification experiments. The lipid material dissolved in nonanoic acid in different concentrations of mixtures was passed through a resin-filled plug-flow reactor at 50 °C and 75 °C with a liquid hourly space velocity (LHSV) of 4 h−1. The oil samples were analyzed for calcium using inductively coupled plasma-optical emission spectrometry, while the resin surfaces were examined by scanning electron microscopy. AL 15 showed a better overall performance and led to a case where over 99% of calcium was removed. Graphical abstract

Sustainable biosurfactant production from secondary feedstock-recent advances, process optimization and perspectives.

Biosurfactants have garnered increased attention lately due to their superiority of their properties over fossil-derived counterparts. While the cost of production remains a significant hurdle to surpass synthetic surfactants, biosurfactants have been anticipated to gain a larger market share in the coming decades. Among these, glycolipids, a type of low-molecular-weight biosurfactant, stand out for their efficacy in reducing surface and interfacial tension, which made them highly sought-after for various surfactant-related applications. Glycolipids are composed of hydrophilic carbohydrate moieties linked to hydrophobic fatty acid chains through ester bonds that mainly include rhamnolipids, trehalose lipids, sophorolipids, and mannosylerythritol lipids. This review highlights the current landscape of glycolipids and covers specific glycolipid productivity and the diverse range of products found in the global market. Applications such as bioremediation, food processing, petroleum refining, biomedical uses, and increasing agriculture output have been discussed. Additionally, the latest advancements in production cost reduction for glycolipid and the challenges of utilizing second-generation feedstocks for sustainable production are also thoroughly examined. Overall, this review proposes a balance between environmental advantages, economic viability, and societal benefits through the optimized integration of secondary feedstocks in biosurfactant production.

Fermentative processes for the upcycling of xylose to xylitol by immobilized cells of Pichia fermentans WC1507.

Xylitol is a pentose-polyol widely applied in the food and pharmaceutical industry. It can be produced from lignocellulosic biomass, valorizing second-generation feedstocks. Biotechnological production of xylitol requires scalable solutions suitable for industrial scale processes. Immobilized-cells systems offer numerous advantages. Although fungal pellet carriers have gained attention, their application in xylitol production remains unexplored. In this study, the yeast strain P. fermentans WC 1507 was employed for xylitol production. The optimal conditions were observed with free-cell cultures at pH above 3.5, low oxygenation, and medium containing (NH4)2SO4 and yeast extract as nitrogen sources (xylitol titer 79.4g/L, YP/S 66.3%, and volumetric productivity 1.3g/L/h). Yeast cells were immobilized using inactive Aspergillus oryzae pellet mycelial carrier (MC) and alginate beads (AB) and were tested in flasks over three consecutive production runs. Additionally, the effect of a 0.2% w/v alginate layer, coating the outer surface of the carriers (cMC and cAB, respectively), was examined. While YP/S values observed with both immobilized and free cells were similar, the immobilized cells exhibited lower final xylitol titer and volumetric productivity, likely due to mass transfer limitations. AB and cAB outperformed MC and cMC. The uncoated AB carriers were tested in a laboratory-scale airlift bioreactor, which demonstrated a progressive increase in xylitol production in a repeated batch process: in the third run, a xylitol titer of 63.0g/L, YP/S of 61.5%, and volumetric productivity of 0.52g/L/h were achieved. This study confirmed P. fermentans WC 1507 as a promising strain for xylitol production in both free- and entrapped-cells systems. Considering the performance of the wild strain, a metabolic engineering intervention aiming at further improving the efficiency of xylitol production could be justified. MC and AB proved to be viable supports for cell immobilization, but additional process development is necessary to identify the optimal bioreactor configuration and fermentation conditions.

Rational biodiesel production from oxidation stability perspective: Evaluation of lipid-soluble carbonyl compound formation in the seed oil and biodiesel with long-term storage

The exploration of appropriate feedstock and catalytic transesterification hinders the practical application of biodiesel. Here, we introduced rational biodiesel production from oxidation stability perspective and evaluated the lipid-soluble carbonyl-containing oxidation products in long-term stored biodiesel samples that prepared from different oil source, catalyst for production, and ester bond type. A stable isotope labeling method based on liquid chromatography-high resolution-mass spectrometry (SIL-LC-HRMS) detection is established using a pair of labeling reagents namely1-(2-hydrazinyl-2-oxoethyl)pyridin-1-ium chloride (GP) and [2H5]1-(2-Hydrazinyl-2-oxoethyl)pyridin-1-ium chloride ([2H5]GP) for lipid-soluble carbonyl-containing oxidation products, including aldehydes and ketones. The main benefits of SIL-LC-HRMS are its sensitivity, selectivity, and feature coverage towards carbonyl-containing compounds and realized their non-targeted screening and relative quantification from complex matrices. Using SIL-LC-HRMS analysis, it was estimated the distribution and formation of 131 carbonyl compounds in three different kinds of second-generation feedstock and biodiesels with one-year storage in the dark. Double bond equivalent (DBE)-number of carbon (nC) plots and hierarchical clustering heatmap analysis reveal the effect of the oil source, catalyst type, and alkyl ester bond type on the variance in carbonyl compound formation during long-term biodiesel storage, arguably the most crucial factor oxidation stability in rational biodiesel production. The carbonyl formation and their variations in biodiesel samples are also discussed by theoretically calculating the bond dissociation energy for the primary constituent of seed oil and biodiesel.

Comparative techno-economics of 1,3-butadiene production from sugarcane feedstocks via ethanol or 2,3-butanediol as intermediates

The global sugar industry has stagnated due to oversupply of the markets with conventional sugar products. Shifting from sugar-only production to co-production of other valuable products, through the integration of biorefineries into existing sugar mills, may open new revenue streams and investment opportunities. The economic feasibilities of various biorefinery scenarios for the production of 1,3-butadiene, by annexation to an existing sugar mill, were investigated. Pathways using either 2,3-butanediol or ethanol as intermediate product were compared, using A-molasses (first-generation), and sugarcane bagasse and brown leaves (second-generation) as feedstocks. The processes were simulated from literature data using Aspen Plus® software for subsequent techno-economic and sensitivity analyses. Producing 1,3-butadiene via the 2,3-butanediol pathway proved to have more attractive economics, with minimum selling prices of 4.08 $/kg and 4.55 $/kg for first-generation-only and integrated/combined first- and second-generation feedstocks, respectively, compared to the ethanol pathway at 5.71 $/kg and 5.72 $/kg. This was mainly attributed to low catalytic performance and higher capital costs associated with the ethanol-to-butadiene catalytic conversion. The investigated scenarios were unprofitable compared to a market price of 1.05 $/kg for fossil-derived 1,3-butadiene, requiring substantial price premiums for bio-based 1,3-butadiene. Instead, the sole production of bio-based 2,3-butanediol as final biorefinery product was deemed to be more viable for investment.

Biodiesel production: An updated review of evidence

This review paper highlights the production of biodiesel from different plant based feedstocks via the transesterification process. Biodiesel is a renewable, non-toxic, environment-friendly and an economically feasible option to tackle the depleting fossil fuels and its negative environmental impact. Biodiesel in general possess higher kinematic viscosity and density than conventional diesel. However, because of food security concerns, the use of edible oil in biodiesel production is criticized globally. Non-edible plant oils, waste cooking oils, and edible oil industry byproducts are suggested as effective biodiesel feedstocks because nonedible feedstock does not compete with food from human consumption. High-potential second-generation feedstock for biodiesel production uses waist cooking oil, acid oil, and animal tallow. Non edible crops in India as a feedstock for biodiesel production are yellow oleander oil (Cascabela thevetia), Pongamia (Pongamia pinnata), Jatropha curcas, Mahua (Madhuca longifolia), Candlenut (Aleurites moluccanus), Rubber (Hevea brasiliensis), Soapnut (Sapindus mukorossi), Jojoba (Simmondsia chinensis), Tobacco (Nicotiana tabacum), Neem (Azadirachta indica), Karanja (Millettia pinnata), Castor (Ricinus communis), Polanga (Calophyllum inophyllum L), Cotton (Gossypium), Kusum (Carthamus tinctorius), Yellow oleander (Cascabela thevetia), Sea mango (Cerbera odollam), Tung (Vernicia fordii), and Bottle tree (Brachychiton rupestris). Biodiesel is a sustainable liquid bio-energy resource that might be used to replace diesel fuel. Despite having numerous advantages over conventional diesel, the biodiesel industry is still struggling in India because of various reasons and challenges like availability, high feedstock pricing, operational hurdles, and supply-chain management challenges.

The transition from 2G to 3G-feedstocks enabled efficient production of fuels and chemicals

For decades micoorganisms have been engineered for the utilization of lignocellulose-based second-generation (2G) feedstocks, but with the concerns of increased levels of atmospheric CO2 causing global warming there is an emergent need to transition from the utilization of 2G feedstocks to third-generation (3G) feedstocks such as CO2 and its derivatives. Here, we established a yeast platform that is capable of simultaneously converting 2G and 3G feedstocks into bulk and value-added chemicals. We demonstrated that by adopting 3G substrates such as CO2 and formate, the conversion of 2G feedstocks could be substantially improved. Specifically, formate could provide reducing power and energy for xylose conversion into valuable chemicals. Simultaneously, it can form a concentrated CO2 pool inside the cell, providing thermodynamically and kinetically favoured amounts of precursors for CO2 fixation pathways, e.g. the Calvin–Benson–Bassham (CBB) cycle. Furthermore, we demonstrated that formate could directly be utilized as a carbon source by yeast to synthesize endogenous amino acids. The engineered strain achieved a one-carbon (C1) assimilation efficiency of 9.2 %, which was the highest efficiency observed in the co-utilization of 2G and 3G feedstocks. We applied this strategy for productions of both bulk and value-added chemicals, including ethanol, free fatty acids (FFAs), and longifolene, resulting in yield enhancements of 18.4 %, 49.0 %, and ∼100 %, respectively. The strategy demonstrated here for co-utilization of 2G and 3G feedstocks sheds lights on both basic and applied research for the up-coming establishment of 3G biorefineries.

An extracellular glucose sensor for substrate-dependent secretion and display of cellulose-degrading enzymes.

The efficient hydrolysis of lignocellulosic biomass into fermentable sugars is key for viable economic production of biofuels and biorenewable chemicals from second-generation feedstocks. Consolidated bioprocessing (CBP) combines lignocellulose saccharification and chemical production in a single step. To avoid wasting valuable resources during CBP, the selective secretion of enzymes (independent or attached to the surface) based on the carbon source available is advantageous. To enable enzyme expression and secretion based on extracellular glucose levels, we implemented a G-protein-coupled receptor (GPCR)-based extracellular glucose sensor; this allows the secretion and display of cellulases in the presence of the cellulosic fraction of lignocellulose by leveraging cellobiose-dependent signal amplification. We focused on the glucose-responsiveness of the HXT1 promoter and engineered PHXT1 by changing its core to that of the strong promoter PTHD3 , increasing extracellular enzyme activity by 81%. We then demonstrated glucose-mediated expression and cell-surface display of the β-glucosidase BglI on the surface of Saccharomyces cerevisiae. The display system was further optimized by re-directing fatty acid pools from lipid droplet synthesis toward formation of membrane precursors via knock-out of PAH1. This resulted in an up to 4.2-fold improvement with respect to the baseline strain. Finally, we observed cellobiose-dependent signal amplification of the system with an increase in enzymatic activity of up to 3.1-fold when cellobiose was added.

The potential of palm bioenergy in achieving Malaysia's renewable energy target and climate ambition in line with the Paris Agreement

Fossil fuel emissions are major contributors to global warming and thus, a primary cause of climate emergency. Many countries ratified the 2015 Paris Agreement to reduce greenhouse gas emissions by replacing fossil fuels with renewables. Malaysia is the second-largest global palm oil producer, and the industry produces large amounts of first-and-second-generation feedstocks that can be used for renewable energy production, but they remain largely untapped. This research evaluated the availability of palm bioenergy in Malaysia and developed a model energy mix that can address Malaysia's targets in line with the Paris Agreement. We found that the annual palm bioenergy potential of 63.5 million tonnes-of-oil-equivalent could theoretically fulfil 64 % of Malaysia's primary energy supply. Approximately 31.7 million tonnes-of-oil-equivalent can be unlocked through our model mix by maximizing the usage of palm-based second-generation feedstocks. These include palm biomass, liquid wastes and by-products that can be used to produce a variety of biofuels, such as biodiesel, biogas and pyrolysis products. As a result, Malaysia can potentially push the renewable energy share in its primary mix to 38 %. This would translate to a reduction in greenhouse gas emission intensity of up to 57 % (based on 2005 levels). Our analysis not only shows that the palm oil industry could play a significant role in Malaysia's decarbonization goal, but it also serves as a basis for the development of a decarbonization framework for other palm oil producing nations around the world. Nevertheless, in moving forward, policy changes, funding and incentives, as well as technological advancement are indeed required to realize this aspiration.

Pursuing single or combined wheat straw based poly(butylene succinate) production routes: A life cycle approach of first- and second-generation feedstocks

The depletion of fossil resources and the climate change crisis call for an urgent shift to production pathways based on renewable and low-carbon sources. In addition, plastic pollution worldwide motivates the identification of new sources for their bio-based counterparts, which have an increasing demand. This research aims to evaluate the environmental feasibility of different cereal-based feedstocks for the production of poly(butylene succinate) (PBS), which is obtained from the polymerisation of succinic acid (SA) and 1,4 butanediol (BDO) monomers. The baseline scenario analysed corresponds to the use of wheat straw as a source of the fermentable sugars. Furthermore, five other cereal-based production routes combining first-generation (1G) feedstocks such as wheat and maize grain, and second-generation (2G) feedstocks, such as sorghum, barley straw, and maize stover, combined with wheat straw, were evaluated. The Life Cycle Assessment (LCA) methodology was used to identify the main hotspots of these valorisation routes at the early stage of the biorefinery design, considering all the burden categories provided by the ReCiPe impact method. The results showed that the straw-based PBS profile reached a Global Warming Potential of 3.43 kg CO2eq, whereas a range value from 2.34 to 7.27 kg CO2eq was estimated when wheat straw is combined with sorghum and barley straw, respectively. The pre-treatment stage represents a substantial impact on the strategy considered to produce fermentable sugars, particularly, for barley straw. Therefore, improvements are still required to reduce the energy demand and increase the sugar yield.

Metabolic engineering of Corynebacterium glutamicum for fatty alcohol production from glucose and wheat straw hydrolysate

BackgroundFatty acid-derived products such as fatty alcohols (FAL) find growing application in cosmetic products, lubricants, or biofuels. So far, FAL are primarily produced petrochemically or through chemical conversion of bio-based feedstock. Besides the well-known negative environmental impact of using fossil resources, utilization of bio-based first-generation feedstock such as palm oil is known to contribute to the loss of habitat and biodiversity. Thus, the microbial production of industrially relevant chemicals such as FAL from second-generation feedstock is desirable.ResultsTo engineer Corynebacterium glutamicum for FAL production, we deregulated fatty acid biosynthesis by deleting the transcriptional regulator gene fasR, overexpressing a fatty acyl-CoA reductase (FAR) gene of Marinobacter hydrocarbonoclasticus VT8 and attenuating the native thioesterase expression by exchange of the ATG to a weaker TTG start codon. C. glutamicum ∆fasR cg2692TTG (pEKEx2-maqu2220) produced in shaking flasks 0.54 ± 0.02 gFAL L−1 from 20 g glucose L−1 with a product yield of 0.054 ± 0.001 Cmol Cmol−1. To enable xylose utilization, we integrated xylA encoding the xylose isomerase from Xanthomonas campestris and xylB encoding the native xylulose kinase into the locus of actA. This approach enabled growth on xylose. However, adaptive laboratory evolution (ALE) was required to improve the growth rate threefold to 0.11 ± 0.00 h−1. The genome of the evolved strain C. glutamicum gX was re-sequenced, and the evolved genetic module was introduced into C. glutamicum ∆fasR cg2692TTG (pEKEx2-maqu2220) which allowed efficient growth and FAL production on wheat straw hydrolysate. FAL biosynthesis was further optimized by overexpression of the pntAB genes encoding the membrane-bound transhydrogenase of E. coli. The best-performing strain C. glutamicum ∆fasR cg2692TTG CgLP12::(Ptac-pntAB-TrrnB) gX (pEKEx2-maqu2220) produced 2.45 ± 0.09 gFAL L−1 with a product yield of 0.054 ± 0.005 Cmol Cmol−1 and a volumetric productivity of 0.109 ± 0.005 gFAL L−1 h−1 in a pulsed fed-batch cultivation using wheat straw hydrolysate.ConclusionThe combination of targeted metabolic engineering and ALE enabled efficient FAL production in C. glutamicum from wheat straw hydrolysate for the first time. Therefore, this study provides useful metabolic engineering principles to tailor this bacterium for other products from this second-generation feedstock.

Opportunities and Challenges of Establishing a Regional Bio-based Polylactic Acid Supply Chain.

Polylactic acid (PLA) is the bioplastic with the highest market share. However, it is mainly produced from first-generation feedstock and there are various inconsistencies in the literature in terms of its production and recycling processes, carbon footprint, and prices. The aim of this study is to compile and contrast these aspects and investigate second-generation PLA production from technical, economic, and ecological perspectives simultaneously. The comprehensive analyses also show the chances and challenges of originating a PLA supply chain in a specific region. Herein, the German Federal State of North Rhine-Westphalia (NRW) has been chosen as a region of interest. In addition to highlighting the industrial capabilities and synergies, the study quantifies and illustrates the locations of different suitable second-generation feedstocks in the region. However, the identified potentials can be challenged by various obstacles such as the high demand of bioresources, feedstock quality, spatial aspects, and logistics. Furthermore, the substantial price gap between PLA and fossil-based plastics can also discourage the investors to include PLA on their portfolios. Thus, the study also provides recommendations to overcome these obstacles and promote the regional value chains of bioplastics which may serve as prototype for other regions.

Assessment of the techno-economic viability of B10 synthesis from second-generation biodiesel feedstocks in Uganda

ABSTRACT This paper assessed the technical and economic viability of biodiesel production from Second-generation feedstocks native to East Africa, which included Castor, Croton, and Jatropha. Their oils were converted to biodiesel by transesterification and characterizations of B100 and B10 done following ASTM D6751. ASPEN Plus V11 was used in process simulation and profitability analysis. Oil yields obtained ranged from 29.5% to 35.6%. B100 and B10 properties conformed to ASTM D6751. The negative Net Present Values obtained render B100 and B10 production uneconomical unless incentivized. Sensitivity analyses showed that NPV varied with feedstock cost and biodiesel selling prices. This assessment established that though a B10 policy based on second-generation feedstocks is technically viable, interventions are needed to make it profitable in Uganda.

Life cycle assessment of biodiesel production from selected second-generation feedstocks

Biodiesel has the potential to substitute conventional diesel and reduce global transport-related greenhouse gas emissions. In this study, the environmental impacts of biodiesel production from three East African second-generation feedstocks: Castor (Ricinus Communis), Croton Megalocarpus, and Jatropha, were assessed in comparison with petroleum-diesel. Inventory data analyzed was obtained from primary and secondary sources in Uganda and existing literature. Life Cycle Assessment methodology was applied in accordance with ISO 14040. Reductions in global warming and human toxicity potentials of up to 7% for B10 biodiesel blends relative to imported petroleum diesel were obtained. Similar reductions were obtained for the other assessed mid-point impact categories. Though relatively very low in absolute terms, this reduction rate is in sync with the target annual reductions of 7.6% and 2.7% required to meet the Paris Agreement temperature targets of 1.5 °C and 2 °C respectively. Transesterification accounted for about 70% of the biodiesel production carbon footprints. Sensitivity analysis revealed that feedstock seed yield per ha is a key determinant of biodiesel's life cycle environmental performance. This study established that B10 from second-generation feedstocks is environmentally more competitive than petroleum-diesel from a life cycle perspective.

Sustainability assessment of the valorization scheme of used cooking oils (UCOs): the case study of Bogotá, Colombia

AbstractHarnessing of second-generation feedstocks via circular economy approaches is generally considered as environmentally friendly. Nonetheless, different potential impacts can be caused during collection and transformation of such feedstocks, affecting overall sustainability. Assessment of such impacts is of particular importance when producing waste-based biofuels. In this regard, this work’s aim was to carry out a sustainability assessment of the existing reclaiming and exploitation strategy of used cooking oil (UCO) in Bogota, Colombia. Currently, UCO is collected, pretreated, and mostly exported to Europe for biodiesel production. Based upon literature data and a life cycle assessment (LCA), several sustainability criteria were derived, measured, and interpreted within the framework of the integrative concept of sustainability (ICoS). As a reference system, results were compared with those obtained from assessing current production of first-generation palm-oil-based biodiesel. Results from LCA indicate that, per ton of UCO-based biodiesel, emissions of 1.06 kg PM2.5-eq, 2.54 kg NOx-eq, 607.6 kg CO2-eq, 2.81 kg SO2-eq, and 0.09 kg P-eq are generated and that there is use of 9.1 m3 water, and 259 kg oil-eq. UCO transportation and biodiesel production stages were the larger contributors to such impacts, and surprisingly, equivalent emissions of CO2 and fossil fuel consumption were higher than those of first-generation biodiesel. Nevertheless, UCO valorization displayed a better overall performance with respect to the reference system in terms of health, safety, environmental, economic, and social indicators. All impacts were reduced by 30 to 50% under a scenario of local production and consumption of biodiesel.