Liquid hot water pretreatment of multi feedstocks and enzymatic hydrolysis of solids obtained thereof

Agricultural feedstocks (brewer spent grains BSG, corncob CC, corn husk CH, wheat straw WS and Luffa sponge LS) were pretreated by liquid hot water (LHW) in order to increase cellulose recovery and enzymatic saccharification. LHW-pretreatment resulted in hemicellulose solubilization, and solids enriched in cellulose. Chemical analysis showed different susceptibilities of the feedstocks to LHW-pretreatment and enzymatic hydrolysis. Pretreated feedstocks presented higher crystallinity (determined through X-ray diffraction) and thermal stability (determined through thermogravimetric analysis) than untreated feedstocks. SEM images confirmed the effect of LHW-pretreatment on structural changes. Moreover, enzymatic hydrolysis and cellulose conversion to glucose (CCG) were improved for pretreated feedstocks, with exception of LS. CCG (in relation to glucose potential on solids) followed the order: BSG>CH>WS>CC>LS. LHW-pretreatment showed to be a good technology to pretreat multi feedstocks and for improving the enzymatic hydrolysis of recalcitrant agricultural feedstocks to sugars, which can be further converted to ethanol-fuel and other value-added chemicals.Michele Michelin is a recipient of a Portuguese Foundation for Science and Technology (FCT) fellowship (SFRH/BPD/100786/2014). This study was supported by the FCT under the scope of the strategic funding of UID/BIO/04469/2013 unit, COMPETE 2020 (POCI-01-0145-FEDER-006684) and the Project RECI/BBB-EBI/0179/2012 (FCOMP-01-0124-FEDER-027462). The authors would like to thank Novozymes A/S for samples of Cellic Ctec2

Ligninolytic enzymes production during polycyclic aromatic hydrocarbons degradation: effect of soil pH, soil amendments and fungal co-cultivation

Soil microorganisms play an important role in the degradation of PAHs and use various metabolic pathways for this process. The effect of soil pH, different soil amendments and the co-cultivation of fungi on the degradation of PAHs in soil and on the activity of ligninolytic enzymes was evaluated. For that purpose, three fungi were studied: Trichoderma viride, Penicillium chrysogenum and Agrocybe aegerita. Biodegradation assays with a mixture of 200 ppm PAHs (fluorene, pyrene, chrysene, and benzo[a]pyrene---50 ppm each) were set up at room temperature for 8 weeks. The maximum laccase activity by solid state fermentation---SSF (7.43 U/g) was obtained by A. aegerita on kiwi peels with 2 weeks and the highest manganese peroxidase activity (7.21 U/g) was reached in 4 weeks, both at pH 7. Fluorene, pyrene, and benzo[a]pyrene achieved higher degradation rates in soil at pH 5, while chrysene was more degradable at pH 7. About 85--90\% of the PAHs were degraded by fungal remediation. The highest degradation of fluorene was achieved by co-cultivation of A. aegerita and P. chrysogenum, remaining 14\% undegradable. Around 13\% of pyrene stay undegradable by A. aegerita and T. viride and by A. aegerita and P. chrysogenum, both systems supported in kiwi peels, while 11\% of chrysene remained in soil by the co-cultivation of these fungi, supported by peanut shells. Regarding benzo[a]pyrene, 13\\% remained in soil after treatment with A. aegerita. Despite the increase in degradation of some PAHs with co-cultivation, higher enzyme production during degradation was observed when fungi were cultivated alone.This study was supported by the Portuguese Foundation for Science and Technology (FCT) under the scope of the research project PTDC/AAG-TEC/5269/2014, the strategic funding of UID/BIO/04469/2013 unit and BioTecNorte operation (NORTE-01-0145-FEDER-000004) funded by the European Regional Development Fund under the scope of Norte2020—Programa Operacional Regional do Norte. Ziva Vipotnik is a recipient of a fellowship supported by a doctoral advanced training (call NORTE-69-2015-15) - Doctoral Program in Applied and Environmental Microbiology (DP_AEM); operation NORTE-08-5369-FSE000060; co-financed by North 2020 through the European Social Fund (ESF).info:eu-repo/semantics/publishedVersio

Biodegradation of chrysene and benzo[a]pyrene and removal of metals from naturally contaminated soil by isolated Trametes versicolor strain and laccase produced thereof

"Available online 11 June 2022"The objective of this study was to assess the degradation rates of chrysene and benzo[a]pyrene, as well as the removal of aluminium and iron from contaminated soil collected in the upper layer (030 cm) in Lagos, Southwest Nigeria. Trametes versicolor was isolated from this soil and used in degradation experiments, with plantain peels as support. After 8 weeks, 82.0% of chrysene degradation was achieved by T. versicolor, and by adding support this increased to 91.0%. Benzo[a]pyrene was less degradable, with 38.0% and 49.1% of degradation, respectively. Trametes versicolor was also capable of accumulate 46.1% of aluminium and 57.2% of iron. By adding plantain peels, these amounts increased to 48.2% and 61.8%, respectively. At the same time, laccase was produced by Trametes versicolor on plantain peels, achieving 37.8 U/g of crude laccase during SSF at 30 °C for 3 weeks. Laccase degradation experiments were set up in packed-bed reactor (PBR), with a constant feed of 21.6 mL/day of laccase, with and without mediators. In 35 days, 75.9% degradation of chrysene was achieved by laccase. The highest degradation was observed with ABTS (2,2-Azino-bis(3-ethylbenzothiazoline-6-sulfonic acid diammonium salt) as mediator, 87.9%. Benzo[a]pyrene degradation with laccase reached 35.6%, raising to 38.8 % with ferulic acid as mediator. In addition, 99.2% of iron and 99.6% of aluminium was removed by laccase, being the treatment for this last mediated with ABTS.This study was supported by the Portuguese Foundation for Science and Technology (FCT), Portugal under the scope of the research project PTDC/AAG-TEC/5269/2014, the strategic funding of UID/BIO/04469/2013 unit and BioTecNorte operation (NORTE-01-0145-FEDER-000004) funded by the European Regional Development Fund under the scope of Norte2020 - Programa Operacional Regional do Norte. Ziva Vipotnik is a recipient of a fellowship supported by a doctoral advanced training (call NORTE-69-2015-15) - Doctoral Program in Applied and Environmental Microbiology (DP_AEM); operation NORTE-08-5369-FSE-000060; co-financed by North 2020 through the European Social Fund (ESF).info:eu-repo/semantics/publishedVersio

Development of a packed bed reactor for the removal of aromatic hydrocarbons from soil using laccase/mediator feeding system

Polyaromatic hydrocarbons (PAH) are persistent pollutants of great concern due to their potential toxicity, mutagenicity and carcinogenicity. A biotechnological approach to remove PAH from soil was evaluated in this work using a laccase mediator system. Initially, laccase was produced by fungal co-cultivation, using kiwi peels as substrate. The produced laccase was applied to PAH contaminated soil to evaluate its efficiency on enzymatic bioremediation. Results showed that laccase mediator system was effective in the degradation of pyrene, fluorene, chrysene and a lower extension anthracene. Mediators improved the PAH degradation and natural mediators (ferulic acid and p-coumaric acid) were as effective as the synthetic mediator ABTS. However, the process was not effective in the benzo[a]pyrene degradation, one of the most recalcitrant and toxic PAH. This low degradation rate could be related to the low activity of the laccase mediator system in an environment lacking water. To overcome this issue, a PAH contaminated soil degradation system was developed in packed bed reactor (PBR) fed with laccase/mediator. Continuous flow of laccase/mediator improved the PAH degradation, achieving 74.8 %, 71.9 %, 72.2 %, 81.8 % and 100 % degradation for fluorene, anthracene, phenanthrene, chrysene and pyrene, respectively. This system was able to degrade 96 % benzo[a]pyrene, which was 90 % higher than the degradation in batch system. Results indicated that the produced laccase as well as the fed-batch degradation system developed in PBR could be successfully applied to the degradation of soil PAH pollutants, with the advantage of achieving higher degradation rates than in simple batch, as well as being a faster and simpler process than microorganism bioremediation.This study was supported by the Portuguese Foundation for Science and Technology (FCT)under the scope of the research project PTDC/AAG-TEC/5269/2014, the strategic funding of UID/BIO/04469/2020 unit and COMPETE 2020 (POCI-01-0145-FEDER-006684) and Bio TecNorte operation (NORTE-01-0145-FEDER-000004) funded by the European Regional Development Fundunder the scope of Norte2020 - Programa Operacional Regional do Norte. Ziva Vipotnik is a recipient of a fellowship supported by a doctoral advanced training (call NORTE-69-2015-15) funded by the European Social Fundunder the scope of Norte2020 - Programa Operacional Regional do Norte.info:eu-repo/semantics/publishedVersio

Degradation of selected PAHs by laccase-mediator system in soil

This study investigated the degradation of selected PAHs using laccase produced through cocultivation of Trichoderma viride (EXF8977) and Penicillium chrysogenum (EXF1818) on solid state fermentation and its mediator system. The main objective of this work was to evaluate the ability of the laccase-mediator systems to degrade PAHs in soil, as well as the effects of natural and synthetic mediators on the laccase activity during the process of PAHs degradation. The laccase production was optimized in packed-bed bioreactor, by testing different airflow (0.05 L min-1 , 0.1 L min-1 and 0.2 L min-1 ), temperature (RT, 30 and 40 °C) and time (2 and 3 weeks) on kiwi peels as substrate using single fungi species and cocultivation. Extracellular laccase activity was measured spectrophotometrically using 0.5 mM 2,2'-azino-bis(3- ethylbenzothiazoline-6-sulphonic acid) (ABTS) as substrate on 420 nm and enzyme activity was expressed in units per millilitre (U/mL). Batch degradation experiments were carried out in 100 mL Erlenmeyer flask on soil pH 5, containing PAH mixture (fluorene, anthracene, pyrene, chrysene and benzo(a)pyrene) from 50 till 600 ppm in dark at 20, 30 and 40 °C. In order to obtain optimum laccase degradation conditions different concentration (0.1 mM, 0.5 mM and 1 mM) of synthetic (ABTS) and natural mediators (p-coumaric acid and ferulic acid) were studied. Samples were collected after 0, 3 and 5 incubation days and the compounds were measured by UHPLC. All the assays including controls were performed in triplicate. Thereafter column packed bed reactor was set up to evaluate the degradation with continue flow (0.015 mL/min) of crude laccase enzyme with 1 mM ABTS, p-coumaric acid and ferulic acid for 25 days, by taking samples each 5 days and evaluating degradation ratio and the remaining concentration of laccase in samples. The selected fungi were able to produce 2.95 U/mL of laccase during SSF in Erlenmeyer flask, however this amount increased with continuous airflow. Highest values were obtained at aeration rates 0.2 L min-1 , with a production of 6.32 U/mL, followed by 0.1 and 0.05 L min -1 with productions of 5.45 and 3.79 U/mL, respectively. Data showed laccase extracted from cocultivation of Penicillium chrysogenum and Trichoderma viride on kiwi peels with an appropriate mediator promoted the degradation of fluorene, anthracene, pyrene, chrysene and benzo(a)pyrene in concentration from 50 ppm till 600 ppm. Reaction system reached highest degradation at 3 days in case of fluorene, chrysene and benzo(a)pyrene, but with anthracene and pyrene maximum degradation rate was observed between 3 and 5 days. The optimizing mediator for fluorene and pyrene was p-coumaric acid, with removal of 81% and 98%, respectively. For anthracene, the best mediator was ABTS with 42% degradation, and laccase with ferulic acid achieved highest degradation rate with chrysene, 61%, and benzo(a)pyrene, 5.4%. However, in packet bed reactor with continuous flow of laccase with mediator at 0.015 mL/min, for 25 days at RT (26- 28 °C), ABTS was found to be the optimum mediator for fluorene, anthracene, chrysene and benzo(a)pyrene, with degradation reaching 74.8 %, 71.9%, 81.8% and 96%, respectively. Around 72.2 % of phenanthrene was degraded with ferulic acid as mediator, and 99.9% degradation of pyrene was reached with p-coumaric acid. Less than 60% degradation rate in 25 days was observed for phenanthrene and anthracene with p-coumaric acid as mediator. The results achieved in the present research demonstrated the utility of laccase from SSF production and its use in bioremediation in soil, especially to reduce the concentration of PAH. However, more research must be done in real conditions.(undefined)info:eu-repo/semantics/publishedVersio

Integration of autohydrolysis and organosolv process for recovery of lignin from corncob

Book of Abstracts of CEB Annual Meeting 2017[Excerpt] Lignocelluloses, such as hardwood, softwood and agricultural residues, are low cost feedstocks mainly composed by cellulose, hemicellulose and lignin. Lignin is the third most abundant naturally synthesized polymer. It presents an amorphous polyphenolic structure, which can be used for the development of bio-based materials and chemicals. However, the bioconversion of renewable lignocelluloses to valueadded products requires their fractionation through pretreatment technologies [1,2]. [...]info:eu-repo/semantics/publishedVersio

Challenges in using ionic liquids for cellulosic ethanol production

The growing need to expand the use of renewable energy sources in a sustainable manner, providing greater energy supply security and reducing the environmental impacts associated with fossil fuels, finds in the agricultural by-product bioethanol an economically viable alternative with significant expansion potential. In this regard, a dramatic boost in the efficiency of processes already in place is required, reducing costs, industrial waste, and our carbon footprint. Biofuels are one of the most promising alternatives to massively produce energy sustainably in a short-term period. Lignocellulosic biomass (LCB) is highly recalcitrant, and an effective pretreatment strategy should also minimize carbohydrate degradation by diminishing enzyme inhibitors and other products that are toxic to fermenting microorganisms. Ionic liquids (ILs) have been playing an important role in achieving cleaner processes as a result of their excellent physicochemical properties and outstanding performance in the dissolution and fractionation of lignocellulose. This review provides an analysis of recent advances in the production process of biofuels from LCB using ILs as pretreatment and highlighting techniques for optimizing and reducing process costs that should help to develop robust LCB conversion processes.This study was supported by the Portuguese Foundation for Science and Technology (FCT) under the scope of the strategic funding of UIDB/04469/2020 unit, and CEECIND/03378/2018; by LABBELS—Associate Laboratory in Biotechnology, Bioengineering and Microelectromechanical Systems, LA/P/0029/2020 and H.R. acknowledges Xunta de Galicia for support through project ED431B 2020/021, co-funded by the European Regional Development Fund, and “Agrupación Europea de Cooperación Territorial—Galicia—Norte de Portugal (GNP-AECT)” for support of a visiting stay at the University of Minho via Iacobus program.info:eu-repo/semantics/publishedVersio

Valorization of wastes from agrofood and pulp and paper industries within the biorefinery concept: southwestern Europe scenario

Nowadays, the need to attain a sustainable society increasingly demands for the development of an economy based on biorefineries. In Southwestern Europe, agrofood and forest industries produce significant amount of wastes that could satisfy the demand for renewable biomass to be used in a biorefinery scheme alternatively to traditional uses of these residues. This chapter will primarily cover the current scenario regarding the annual volume of residues generated by agrofood (cheese whey, vine pruning waste, and brewer's spent grains) and pulp and paper industry (sawdust, chips, bark, and sludge). Additionally, the present-day use and final destination of these wastes and their main environmental issues will be described and discussed; besides, advanced valorization strategies (e.g., fuels and chemicals) involving a biorefinery approach will be approached, based on current reports according to the chemical composition of each waste. Finally, new insights on valorization of wastes from agrofood and pulp and paper industries, its challenges, and trends for future research will be presented.(undefined)info:eu-repo/semantics/publishedVersio

Liquid hot water pretreatment of multi feedstocks and enzymatic hydrolysis of solids obtained thereof

h i g h l i g h t s Chemical composition showed different susceptibility of multi feedstocks to LHW. LHW improved thermal properties and structural characteristics of multi feedstocks. The crystallinity degree of multi feedstocks increased after LHW-pretreatment. Cellulose conversion to glucose rate was higher in brewers' spent grain and corn husk. t r a c t Agricultural feedstocks (brewers' spent grain -BSG, corncob -CC, corn husk -CH, wheat straw -WS and Luffa sponge -LS) were pretreated by liquid hot water (LHW) in order to increase cellulose recovery and enzymatic saccharification. LHW-pretreatment resulted in hemicellulose solubilization, and solids enriched in cellulose. Chemical analysis showed different susceptibilities of the feedstocks to LHWpretreatment and enzymatic hydrolysis. Pretreated feedstocks presented higher crystallinity (determined through X-ray diffraction) and thermal stability (determined through thermogravimetric analysis) than untreated feedstocks. SEM images confirmed the effect of LHW-pretreatment on structural changes. Moreover, enzymatic hydrolysis and cellulose conversion to glucose (CCG) were improved for pretreated feedstocks, with exception of LS. CCG (in relation to glucose potential on solids) followed the order: BSG > CH > WS > CC > LS. LHW-pretreatment showed to be a good technology to pretreat multi feedstocks and for improving the enzymatic hydrolysis of recalcitrant agricultural feedstocks to sugars, which can be further converted to ethanol-fuel and other value-added chemicals