Optimization of lipase production by solid-state fermentation of olive pomace: from flask to laboratory-scale packed-bed bioreactor

Lipases are versatile catalysts with many applications and can be produced by solid-state fermentation (SSF) using agro-industrial wastes. The aim of this work was to maximize the production of Aspergillus ibericus lipase under SSF of olive pomace (OP) and wheat bran (WB), evaluating the effect on lipase production of C/N ratio, lipids, phenols, content of sugars of substrates and nitrogen source addition. Moreover, the implementation of the SSF process in a packed-bed bioreactor and the improvement of lipase extraction conditions were assessed. Low C/N ratios and high content of lipids led to maximum lipase production. Optimum SSF conditions were achieved with a C/N mass ratio of 25.2 and 10.2% (w/w) lipids in substrate, by the mixture of OP:WB (1:1) and supplemented with 1.33% (w/w) (NH4)2SO4. Studies in a packed-bed bioreactor showed that the lower aeration rates tested prevented substrate dehydration, improving lipase production. In this work, the important role of Triton X-100 on lipase extraction from the fermented solid substrate has been shown. A final lipase activity of 223 ± 5 U g1 (dry basis) was obtained after 7 days of fermentation.Felisbela Oliveira acknowledges the financial support from Fundação para a Ciência e Tecnologia (FCT) of Portugal through grant SFRH/BD/87953/2012. José Manuel Salgado was supported by grant CEB/N2020–INV/01/2016 from Project ‘‘BIOTECNORTE-Underpinning Biotechnology to foster the north of Portugal bioeconomy’’ (NORTE-01-0145-FEDER-000004). Luı ´s Abrunhosa was supported by grant UMINHO/BPD/51/2015 from project UID/BIO/04469/2013 financed by FCT/MEC (OE). This study was supported by the Portuguese Foundation for Science and Technology (FCT) under the scope of the strategic funding of UID/BIO/04469/2013 unit and COMPETE 2020 (POCI-01-0145-FEDER006684) and BioTecNorte operation (NORTE-01-0145-FEDER000004) funded by the European Regional Development Fund under the scope of Norte2020–Programa Operacional Regional do Norte. Noelia Pérez-Rodríguez acknowledges the financial support of FPU fellowship from the Spanish Ministry of Education, Culture and Sports. The authors thank the Spanish Ministry of Economy and Competitiveness for the financial support of this work (Project CTQ2015-71436-C2-1-R), which has partial financial support from the FEDER funds of the European Union.info:eu-repo/semantics/publishedVersio

Influence of Temperature and Drying Time on Extraction Yield of Phenolic Compounds from Grape Pomace Variety “Portogizac”

The influence of drying temperature (60 °C, 70 °C, 80 °C) and fluid-bed drying time (90 min, 135 min, 180 min) on the extraction yield of phenolic compounds and antioxidant activity of extracts were investigated. The content of phenolic compounds and antioxidant activity of extracts obtained from wet grape pomace (WGP) were 73.83 mgGAE gdb–1, 42.24 mgCE gdb–1, 30.53 mg gdb–1, and 0.35 ginhDPPH gdb–1 for total phenolic compounds (TPC), total flavonoids (TF), total extractible proanthocyanidins (TPA), and antioxidant activity (AA), respectively. The applied drying conditions caused the reduction of content of all phenolic compounds down to 13.2 %, 43.1 %, 15.3 % and 21.0 % for TPC, TPA, TF and AA, respectively. The most abundant individual phenolic compound in grape pomace extracts was catechin (5.14 – 8.52 mg gdb–1). The highest content of observed compounds was retained when applying drying temperature below 70 °C for 90 minutes

Impact of heat treatment and acid gelation on polyphenol enriched milk samples

The effects of heat treatment and the stage of polyphenol addition to milk before or after heat treatment on the total phenolic content (TPC), ferric-ion reducing antioxidant power (FRAP), pH, casein micelle size (CMS) and whey protein denaturation content of milk-polyphenol mixtures were investigated. Four sources of phenolic compounds (green tea, white grape, tannic acid, gallic acid) were incorporated into pasteurized-skim milk. A heat treatment (85 °C for 30 min) was applied to pasteurized-skim milk either before (MhP) or after polyphenols addition (MhPh). Acid milk gels were produced using MhPh samples, and their TPC and FRAP were determined. Heat treatment decreased the TPC and FRAP values of the samples, except for tannic acid, probably due to increased polyphenol-protein interactions. However, MhPh tannic acid sample resulted in significantly higher FRAP value than MhP. The addition of gallic acid before heat treatment (MhPh) significantly increased CMS due to the lower pH of this sample during heating. Acid gelation decreased the extractable polyphenols, however there was no significant different on FRAP between acid gel and MhPh milk samples. This study showed that the properties of phenolic source, particularly pH, and the stage of polyphenol addition to milk had an impact on selected properties

COVID-19 infection is a significant risk factor for death in patients presenting with acute cholecystitis: a secondary analysis of the ChoCO-W cohort study

Background: During the coronavirus disease (COVID-19) pandemic, there has been a surge in cases of acute cholecystitis. The ChoCO-W global prospective study reported a higher incidence of gangrenous cholecystitis and adverse outcomes in COVID-19 patients. Through this secondary analysis of the ChoCO-W study data, we aim to identify significant risk factors for mortality in patients with acute cholecystitis during the COVID-19 pandemic, emphasizing the role of COVID-19 infection in patient outcomes and treatment efficacy.” Methods: The ChoCO-W global prospective study reported data from 2546 patients collected at 218 centers from 42 countries admitted with acute cholecystitis during the COVID-19 pandemic, from October 1, 2020, to October 31, 2021. Sixty-four of them died. Nonparametric statistical univariate analysis was performed to compare patients who died and patients who survived. Significant factors were then entered into a logistic regression model to define factors predicting mortality. Results: The significant independent factors that predicted death in the logistic regression model with were COVID-19 infection (p < 0.001), postoperative complications (p < 0.001), and type (open/laparoscopic) of surgical intervention (p = 0.003). The odds of death increased 5 times with the COVID-19 infection, 6 times in the presence of complications, and it was reduced by 86% with adequate source control. Survivors predominantly underwent urgent laparoscopic cholecystectomy (52.3% vs. 23.4%). Conclusions: COVID-19 was an independent risk factor for death in patients with acute cholecystitis. Early laparoscopic cholecystectomy has emerged as the cornerstone of treatment for hemodynamically stable patients