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- ItemLimited life cycle andcost assessment for the bioconversion of lignin‐derived aromatics into adipic acid(New York, NY [u.a.] : Wiley, 2020) van Duuren, Jozef B.J.H.; de Wild, Paul J.; Starck, Sören; Bradtmöller, Christian; Selzer, Mirjam; Mehlmann, Kerstin; Schneider, Roland; Kohlstedt, Michael; Poblete‐Castr, Ignacio; Stolzenberger, Jessica; Barton, Nadja; Fritz, Michel; Scholl, Stephan; Venus, Joachim; Wittmann, ChristophLignin is an abundant and heterogeneous waste byproduct of the cellulosic industry, which has the potential of being transformed into valuable biochemicals via microbial fermentation. In this study, we applied a fast-pyrolysis process using softwood lignin resulting in a two-phase bio-oil containing monomeric and oligomeric aromatics without syringol. We demonstrated that an additional hydrodeoxygenation step within the process leads to an enhanced thermochemical conversion of guaiacol into catechol and phenol. After steam bath distillation, Pseudomonas putida KT2440-BN6 achieved a percent yield of cis, cis-muconic acid of up to 95 mol% from catechol derived from the aqueous phase. We next established a downstream process for purifying cis, cis-muconic acid (39.9 g/L) produced in a 42.5 L fermenter using glucose and benzoate as carbon substrates. On the basis of the obtained values for each unit operation of the empirical processes, we next performed a limited life cycle and cost analysis of an integrated biotechnological and chemical process for producing adipic acid and then compared it with the conventional petrochemical route. The simulated scenarios estimate that by attaining a mixture of catechol, phenol, cresol, and guaiacol (1:0.34:0.18:0, mol ratio), a titer of 62.5 (g/L) cis, cis-muconic acid in the bioreactor, and a controlled cooling of pyrolysis gases to concentrate monomeric aromatics in the aqueous phase, the bio-based route results in a reduction of CO2-eq emission by 58% and energy demand by 23% with a contribution margin for the aqueous phase of up to 88.05 euro/ton. We conclude that the bio-based production of adipic acid from softwood lignins brings environmental benefits over the petrochemical procedure and is cost-effective at an industrial scale. Further research is essential to achieve the proposed cis, cis-muconic acid yield from true lignin-derived aromatics using whole-cell biocatalysts. © 2020 Wiley Periodicals, Inc.
- ItemBatch and continuous lactic acid fermentation based on a multi-substrate approach(Basel : MDPI AG, 2020) Olszewska-Widdrat, Agata; Alexandri, Maria; López-Gómez, José Pablo; Schneider, Roland; Venus, JoachimThe utilisation of waste materials and industrial residues became a priority within the bioeconomy concept and the production of biobased chemicals. The aim of this study was to evaluate the feasibility to continuously produce L-lactic acid from different renewable substrates, in a multi-substrate strategy mode. Based on batch experiments observations, Bacillus coagulans A534 strain was able to continuously metabolise acid whey, sugar beet molasses, sugar bread, alfalfa press green juice and tapioca starch. Additionally, reference experiments showed its behaviour in standard medium. Continuous fermentations indicated that the highest productivity was achieved when molasses was employed with a value of 10.34 g·L−1·h−1, while the lactic acid to sugar conversion yield was 0.86 g·g−1 . This study demonstrated that LA can be efficiently produced in continuous mode regardless the substrate, which is a huge advantage in comparison to other platform chemicals. © 2020 by the authors. Licensee MDPI, Basel, Switzerland.
- ItemIntegration of Solid State and Submerged Fermentations for the Valorization of Organic Municipal Solid Waste(Basel : MDPI, 2021) Martău, Gheorghe-Adrian; Unger, Peter; Schneider, Roland; Venus, Joachim; Vodnar, Dan Cristian; López-Gómez, José PabloSolid state fermentation (SsF) is recognized as a suitable process for the production of enzymes using organic residues as substrates. However, only a few studies have integrated an evaluation of the feasibility of applying enzymes produced by SsF into subsequent hydrolyses followed by the production of target compounds, e.g., lactic acid (LA), through submerged-liquid fermentations (SmF). In this study, wheat bran (WB) was used as the substrate for the production of enzymes via SsF by Aspergillus awamori DSM No. 63272. Following optimization, cellulase and glucoamylase activities were 73.63 ± 5.47 FPU/gds and 107.10 ± 2.63 U/gdb after 7 days and 5 days of fermentation, respectively. Enzymes were then used for the hydrolysis of the organic fraction of municipal solid waste (OFMSW). During hydrolysis, glucose increased considerably with a final value of 19.77 ± 1.56 g/L. Subsequently, hydrolysates were fermented in SmF by Bacillus coagulans A166 increasing the LA concentration by 15.59 g/L. The data reported in this study provides an example of how SsF and SmF technologies can be combined for the valorization of WB and OFMSW.
- ItemOrganic fraction of municipal solid waste for the production of L-lactic acid with high optical purity(2020) López-Gómez, José Pablo; Alexandri, Maria; Schneider, Roland; Latorre-Sánchez, Marcos; Coll Lozano, Caterina; Venus, JoachimThe organic fraction of municipal solid waste (OFMSW) is an abundant biowaste with great potential in the bioeconomy model. Previous reports have demonstrated that OFMSW hydrolysates are good substrates for lactic acid (LA) production. However, LA can exist in two enantiomeric forms (L- and D-) and most commercial LA applications require a high enantiomeric purity, typically of the L-isomer. Due to natural occurring bacteria in the waste, a mixture of D- and L-LA can form in the substrate, reducing the final enantiomeric purity of the product and limiting its commercial application. In the research reported in this article, hydrolysates from OFMSW were evaluated for the production L-LA with high enantiomeric purity. Firstly, a pre-treatment with monopolar electrodialysis membranes was implemented to remove the unfavourable D-LA in the hydrolysate. This step allowed the reduction in LA concentration and subsequent fermentations of the hydrolysate resulted in enantiomeric purities over 98%. At the pilot scale, a fermentation of the pre-treated hydrolysate, by B. coagulans A166, resulted in a final LA concentration of 61.1 g L−1 and a yield of 0.94 g g−1. The downstream of the process resulted on a LA recovery of 51.5% and a L-LA optical purity of 98.7%.