The screening of sustainable agro-industrial biorefinery pathways for the production of bio-based products and energy is a complex challenge and needs investigation. Critical tools for predicting the ...commercialization feasibility of biorefining pathway includes laboratory and pilot-scale experimental results, processes modeling, technoeconomic and market analysis. The objective of the present study was the potential pathways experimental proof of concept of the sunflower meal (SFM), by-product in the sunflower oil production process, at TRL3-4 level, in an effort to assist the bio-based industries in evaluating the profitability of different possible production routes and product portfolios. Taking a reflexive approach, various processes and products were investigated, adding insights in the technical feasibility of conversion towards multi-product pathways at lab scale. Many sets of experiments were conducted in two laboratories, investigating SFM biorefining using physical, biological and thermochemical processes (fractionation, fermentation, enzymatic hydrolysis and pyrolysis) for the production of various added-value products, biochar and energy carriers. Product yields, mass balances, Effective Mass Yield (EMY) and Feature Complexity (FC) were estimated for each pathway. The study demonstrated that SFM cascade refining concept is feasible leading to the production of antioxidants, protein isolate, biochar, bioenergy carriers (pyro-oil and pyro-gas) and also poly(3-hydroxybutyrate) and microbial oil with a Feature Complexity (FC): 6-7. The studied pathways were based on the principle of optimised resource utilisation. Pyrolytic chars showed suitable for soil amendment, thus, closing the loop in agriculture (from land-to-land). The study demonstrated at TRL3-4, alternative pathways for sifting from a mono-to-multiple process and product agricultural industry (Grey biotechnology), in the context of Circular Bioeconomy and provided experimental protocols.
•Reflexive TRL2-4 approaches in the content of Circular Bio Economy.•Valorization of sunflower meal through a cascade bio-refinery approach.•Shifting from a mono-to a multiple-product agricultural Industry.•Antioxidants, protein, microbial oil, PHB and bio-char from sunflower meal.
Sulfate is of great importance in anaerobic digestion as its addition can help control the microbial community. In this study, the effect of sulfuric acid addition on the performance of a UASB ...reactor fed with hydrolyzed starch was investigated. The total organic carbon (TOC), Fe, SO42− removal and methane production were monitored under various chemical oxygen demand (COD) to SO42− ratios, hydraulic retention times (HRTs) and organic loading rates (OLRs). When the HRT was 16 h, and the OLR was equal to 2 g COD/LUASB-day, methane production was 0.24 L CH4/LUASB-day. After the addition of sulfuric acid, TOC removal reached 95%, and the population of Ruminococcus sp. that utilize soluble carbohydrates increased by 19.7%. Nitrogen removal was less than 25%, while the population of Ignavibacterium sp. accounted for 2.3%. When the HRT, OLR and COD/SO42− ratios were equal to 16 h, 2 g COD/LUASB-d and 3.72, respectively, methane production was 0.267 L CH4/LUASB-day. When the OLR increased to 5.94 g, the COD/LUASB-day and COD/SO42− ratios were equal to 12.5, and methane production was three times higher (0.84 L CH4/LUASB-day), with a methane content in the produced biogas greater than 70% due to the increased amount of Methanosaeta sp. and direct interspecies electron transfer. Sulfate addition increased the relative abundance of Desulfovibrio sp., accounting for 9.9% and an iron accumulation exceeding 98.0%. This study indicates that appropriate sulfate concentrations in the feed in combination with the presence of iron in the UASB lead to enhanced methane yields.
This study aims to investigate the use of Fenton reagents for the efficient hydrolysis of starch, an industrial by-product obtained from the potato processing industry. A full factorial design ...experiment (FFD) was conducted and a statistical model was developed for simulating the hydrolysis process. The most important factors were the hydrolysis temperature and the amount of H2O2 followed by the interaction of FeSO4·7H2O and temperature. At maximum levels of FeSO4·7H2O (1.00g/L), H2O2 (0.51 g/L), and temperature (70.0 °C), a 99.5% hydrolysis yield was achieved, with a carbohydrate content of 28.65 g/L. Furthermore, analysis of hydrolysis kinetics demonstrated that an increased concentration of FeSO4·7H2O results in a decelerated rate of starch hydrolysis. Moreover, biodegradability tests were carried out to estimate the methane production potential from the produced hydrolysates. The specific methanogenic activity (SMA) was reached at 0.669 ± 0.014 g CH4-COD g−1 VSS day−1 proving the effectiveness of the hydrolysis process and highlighting the potential of industrial starch for bioenergy production. A preliminary cost analysis showed that a small investment for utilizing the starch in an existing wastewater treatment facility of a potato processing company becomes profitable before the end of the 3rd year, obtaining a net present value (NPV) 37.5% higher than that of the current utilization scenario.
Formic, acetic, and succinic acids have been selectively separated from their mixture obtained by A. succinogenes fermentation using reactive extraction with tri-n-octylamine (TOA) dissolved in three ...solvents with different polarities (n-heptane, butyl acetate, and dichloromethane) without and with 1-octanol addition. This technique allows recovering formic and acetic acids from the mixture, the raffinate containing only succinic acid. The extractant concentration and organic phase polarity control the selectivity of acids extraction. Thus, at pH = 1, the selectivity factor increased from 92, in the absence of 1-octanol; to 148, in the presence of this alcohol in organic phase. The corresponding optimum concentrations of TOA in the solvent were 30 and 50 g/l, respectively. The total separation of monocarboxylic acids from the mixture with succinic acid is possible by a multi-stage extraction process, adjusting the extractant concentration in each stage to that stoechiometrically needed for reactions with formic and acetic acids only. The addition of 1-octanol reduces the number of required extraction stages.
The bio-based platform chemicals 2,3-butanediol (BDO) and acetoin have various applications in chemical, cosmetics, food, agriculture, and pharmaceutical industries, whereas the derivatives of BDO ...could be used as fuel additives, polymer and synthetic rubber production. This review summarizes the novel technological developments in adapting genetic and metabolic engineering strategies for selection and construction of chassis strains for BDO and acetoin production. The valorization of renewable feedstocks and bioprocess development for the upstream and downstream stages of bio-based BDO and acetoin production are discussed. The techno-economic aspects evaluating the viability and industrial potential of bio-based BDO production are presented. The commercialization of bio-based BDO and acetoin production requires the utilization of crude renewable resources, the chassis strains with high fermentation production efficiencies and development of sustainable purification or conversion technologies.
•Metabolic engineering focus on 2,3-butanediol and acetoin production.•Renewable resources and bioprocessing conditions are considered.•Oxygen supply could be used to control 2,3-butanediol or acetoin production.•Techno-economic aspects of bio-based 2,3-butanediol production are discussed.•Evaluation of 2,3-butanediol and acetoin as bio-based platform chemicals.
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•A review on valorization processes for food manufacturing waste was performed.•Feedstock security, techno-economic, and environmental aspects were analyzed.•Most of the valorization ...pathways analyzed are developed only at lab scale.•Relevant aspects to ensure sustainability of biorefineries are barely considered.
The need to increase circularity of industrial systems to address limited resources availability and climate change has triggered the development of the food waste biorefinery concept. However, for the development of future sustainable industrial processes focused on the valorisation of food waste, critical aspects such as (i) the technical feasibility of the processes at industrial scale, (ii) the analysis of their techno-economic potential, including available quantities of waste, and (iii) a life cycle-based environmental assessment of benefits and burdens need to be considered. The goal of this review is to provide an overview of food waste valorisation pathways and to analyse to which extent these aspects have been considered in the literature. Although a plethora of food waste valorisation pathways exist, they are mainly developed at lab-scale. Further research is necessary to assess upscaled performance, feedstock security, and economic and environmental assessment of food waste valorisation processes.
The transition from a fossil fuel-based economy to a bio-based economy necessitates the exploitation of synergies, scientific innovations and breakthroughs, and step changes in the infrastructure of ...chemical industry. Sustainable production of chemicals and biopolymers should be dependent entirely on renewable carbon. White biotechnology could provide the necessary tools for the evolution of microbial bioconversion into a key unit operation in future biorefineries. Waste and by-product streams from existing industrial sectors (e.g., food industry, pulp and paper industry, biodiesel and bioethanol production) could be used as renewable resources for both biorefinery development and production of nutrient-complete fermentation feedstocks. This review focuses on the potential of utilizing waste and by-product streams from current industrial activities for the production of chemicals and biopolymers via microbial bioconversion. The first part of this review presents the current status and prospects on fermentative production of important platform chemicals (i.e., selected C2-C6 metabolic products and single cell oil) and biopolymers (i.e., polyhydroxyalkanoates and bacterial cellulose). In the second part, the qualitative and quantitative characteristics of waste and by-product streams from existing industrial sectors are presented. In the third part, the techno-economic aspects of bioconversion processes are critically reviewed. Four case studies showing the potential of case-specific waste and by-product streams for the production of succinic acid and polyhydroxyalkanoates are presented. It is evident that fermentative production of chemicals and biopolymers via refining of waste and by-product streams is a highly important research area with significant prospects for industrial applications.
•Detailed Life Cycle Inventory & cradle-to-gate LCA of PHB production from soybean oil and sucrose as fermentation feedstock.•Comparison with previous LCA studies on PHB production as well as on ...fossil-based polymers such as HDPE and PP.•Provision, as supplementary material, of all calculations for designing the PHB production bioprocesses and LCI/LCA analysis.
There is a wide variability on the environmental analysis employing life cycle assessment (LCA) of bio-based polymers produced via fermentation especially in the case of poly(3-hydroxybutyrate) (PHB). The main aim of this study is the evaluation of greenhouse gas (GHG) emissions, non-renewable energy use (NREU), acidification potential (AP) and eutrophication potential (EP) of PHB production. These results have been compared with literature-cited studies and petroleum-derived counterparts. The results demonstrate that, apart from methodological issues and shortcomings inherent to the LCA methodology, various parameters (e.g. selection of raw materials, adopted allocation methodology) affect the variability observed in previous studies. It is also demonstrated that PHB production has definite and undisputed advantages over its petrochemical alternatives that are currently produced on a massive scale.
In this work we explore the concept of integrated biorefineries, and we examine alternative schemes for the co-production of biofuels (biodiesel) and chemicals (succinic acid). Four different ...biorefinery schemes considering the different uses of crude glycerine from the biodiesel process are simulated and compared: (i) the disposal of crude glycerine as a waste, (ii) the purification (through distillation) of crude glycerine to 80%, (iii) the purification of glycerine to 95%. and (iv) the production of succinic acid from glycerine through fermentation. For the latter, we consider the bioprocess that converts the glycerol to succinate, and a downstream separation process that purifies and crystallises our product to the final succinic acid crystals. To apply complex kinetics for the fermentation we have linked Aspen Plus (2006.5) with Matlab (R2007b), where we have used the experimentally-based unstructured model from Vlysidis et al., 2009 and 2010. We first determine the operating parameters of the fermentor that have a significant effect on the economics of this scenario, i.e. the cycle time of the batch fermentation and the water flowrate entering the bioreactor. Subsequently, we perform single- and multi-objective optimisation to maximise the profit and/or to minimise the environmental impact of the overall process. We then analyse and compare the economics of the four different biorefinery schemes by using well-known profitability and/or emission criteria. Furthermore, we carry out sensitivity analysis that takes into consideration price variations for the most important materials and we extract firm conclusions about the profitability of each scenario. It is found that succinic acid co-production can enhance the profit of the overall biorefinery by 60% for a 20 years plant lifetime. These results indicate the importance of glycerol when it is utilised as a key renewable building block for the production of commodity chemicals.
►We simulate alternative schemes for integrated biorefineries highlighting the co-production of fuels and chemicals through glycerol bioconversion to succinic acid. ► We perform single- and multi-objective optimization to compute optimal operating conditions that maximize biorefinery profitability and control CO
2 emissions. ► We perform extensive economic analysis using measurements like Net Present Value and Internal Rate of Return robustly comparing biorefinery schemes.► We perform sensitivity analysis considering price fluctuations for raw materials, products/byproducts assessing profitability of biorefineries under different economic scenarios.
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