Response surface statistical optimization of bacterial nanocellulose fermentation in static culture using a low-cost medium

Supplementary material related to this article can be found, in the online version, at doi:https://doi.org/10.1016/j.nbt.2018.12.002.This work aimed at the optimization of bacterial nanocellulose (BNC) production by static culture, using Komagataeibacter xylinus BPR 2001 (K. xylinus). Response surface methodology - central composite design was used to evaluate the effect of inexpensive and widely available nutrient sources, namely molasses, ethanol, corn steep liquor (CSL) and ammonium sulphate, on BNC production yield. The optimized parameters for maximum BNC production were % (m/v): molasses 5.38, CSL 1.91, ammonium sulphate 0.63, disodium phosphate 0.270, citric acid 0.115 and ethanol 1.38 % (v/v). The experimental and predicted maximum BNC production yields were 7.5±0.54g/L and 6.64±0.079g/L, respectively and the experimental and predicted maximum BNC productivity were 0.829±0.046g/L/day and 0.734±0.079g/L/day, after 9 days of static culture fermentation, at 30°C. The effect of surface area and culture medium depth on production yield and productivity were also studied. BNC dry mass production increased linearly with surface area, medium depth and fermentation time. So long as nutrients were still available in the culture media, BNC mass productivity was constant. The results show that a high BNC production yield can be obtained by static culture of K. xylinus BPR 2001 using a low-cost medium. These are promising conditions for the static industrial scale BNC production, since as compared to agitated bioreactors, higher productivities may be reached, while avoiding high capital and operating costs.The authors would like to acknowledge the Portuguese Foundation for Science and Technology (FCT) for the financial support of the PhD grant SFRH/BD/89547/2012 attributed to Ana Cristina Rodrigues, the financial support from project SkinChip: Disruptive cellulose-based microfluidic device for 3D skin modelling, PTDC/BBB-BIO/1889/2014. ThisstudywasalsosupportedbythePortugueseFoundationforScience 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-FEDER-000004) funded by European Regional Development Fund under the scope of NORTE 2020 - Programa Operacional Regional do Norte. The authors acknowledge COPAM Companhia Portuguesa de Amidos, S.A. (Portugal) and RAR Refinarias de Açúcar Reunidas, S.A. (Portugal) for kindly providing CSL and molasses, respectively.info:eu-repo/semantics/publishedVersio

Far-reaching cellular consequences of tat deletion in Escherichia coli revealed by comprehensive proteome analyses

In Escherichia coli, the Twin-arginine translocation (Tat) pathway secretes a set of folded proteins with important physiological functions to the periplasm and outer membrane. The loss of Tat secretion impairs outer membrane integrity and leads to decreased cell growth. Only recently, the Tat pathway has gained more attention due to its essential role in bacterial virulence and applications in the production of fully folded heterologous proteins. In this study, we investigated the influence of the deletion of all active Tat pathway components on the E. coli cells. The comprehensive proteomic analysis revealed activation of several stress responses and experimentally confirmed the dependence of certain proteins on the Tat system for export. We observed that a tat deletion triggers protein aggregation, membrane vesiculation, synthesis of colanic acid and biofilm formation. Furthermore, the mislocalization of Tat-dependent proteins disturbs iron and molybdenum homeostasis and impairs the cell envelope integrity. The results show that the functional Tat pathway is important for the physiological stability and that its dysfunction leads to a series of severe changes in E. coli cells

Reducing the environmental impact of surgery on a global scale: systematic review and co-prioritization with healthcare workers in 132 countries

Abstract Background Healthcare cannot achieve net-zero carbon without addressing operating theatres. The aim of this study was to prioritize feasible interventions to reduce the environmental impact of operating theatres. Methods This study adopted a four-phase Delphi consensus co-prioritization methodology. In phase 1, a systematic review of published interventions and global consultation of perioperative healthcare professionals were used to longlist interventions. In phase 2, iterative thematic analysis consolidated comparable interventions into a shortlist. In phase 3, the shortlist was co-prioritized based on patient and clinician views on acceptability, feasibility, and safety. In phase 4, ranked lists of interventions were presented by their relevance to high-income countries and low–middle-income countries. Results In phase 1, 43 interventions were identified, which had low uptake in practice according to 3042 professionals globally. In phase 2, a shortlist of 15 intervention domains was generated. In phase 3, interventions were deemed acceptable for more than 90 per cent of patients except for reducing general anaesthesia (84 per cent) and re-sterilization of ‘single-use’ consumables (86 per cent). In phase 4, the top three shortlisted interventions for high-income countries were: introducing recycling; reducing use of anaesthetic gases; and appropriate clinical waste processing. In phase 4, the top three shortlisted interventions for low–middle-income countries were: introducing reusable surgical devices; reducing use of consumables; and reducing the use of general anaesthesia. Conclusion This is a step toward environmentally sustainable operating environments with actionable interventions applicable to both high– and low–middle–income countries

Geflüchtete an Hochschulen – Betrachtungen im Rahmen von Diversity Strategien

Sievers I. Geflüchtete an Hochschulen – Betrachtungen im Rahmen von Diversity Strategien. In: Sievers I, Grawan F, eds. Fluchtmigration, gesellschaftliche Teilhabe und Bildung. Handlungsfelder und Erfahrungen. Frankfurt a. Main: Brandes & Apsel; 2017: 110-127

Die Arbeit mit Geflüchteten. Zwischen ehrenamtlichem Engagement und pädagogischer Professionalisierung im Bereich der Sprachlernunterstützung

Sievers I, Hauschild J. Die Arbeit mit Geflüchteten. Zwischen ehrenamtlichem Engagement und pädagogischer Professionalisierung im Bereich der Sprachlernunterstützung. In: Sievers I, Grawan F, eds. Fluchtmigration, gesellschaftliche Teilhabe und Bildung. Handlungsfelder und Erfahrungen. Frankfurt a. Main: Brandes & Apsel; 2017: 140-155

Diversity Education im Übergang von der KiTa zur Grundschule - Am Beispiel eines Modellprojektes

Sievers I. Diversity Education im Übergang von der KiTa zur Grundschule - Am Beispiel eines Modellprojektes. In: Hauenschild K, Robak S, Sievers I, eds. Diversity Education. Zugänge - Perspektiven - Beispiele. Bildung in der Weltgesellschaft. Vol 6. Frankfurt am Main: Brandes und Apsel Verlag; 2013: S. 266-287

Von Diversität, Anerkennung und Transmigration. Das Beispiel bildungserfolgreicher Transmigrant/innen

Sievers I. Von Diversität, Anerkennung und Transmigration. Das Beispiel bildungserfolgreicher Transmigrant/innen. Talente. Zeitschrift für Bildung, Berufsorientierung und Personalentwicklung. 2013:24-34

Vielfalt und Elternarbeit. Chancen und Herausforderungen im Umgang mit zunehmender Diversität.

Sievers I. Vielfalt und Elternarbeit. Chancen und Herausforderungen im Umgang mit zunehmender Diversität. Die Grundschulzeitschrift. 2016;Heft 298.299:10-12

Unabgeschlossene Wanderungsprozesse. Das Beispiel hochqualifizierter Transmigranten

Sievers I. Unabgeschlossene Wanderungsprozesse. Das Beispiel hochqualifizierter Transmigranten. EinBlick. Das @Themenheft der Agentur für Erwachsenen- und Weiterbildung. 2012;2012(1 (Migration):11

Anforderungen an Hochschulabsolvierende in Zeiten von Diversität

Sievers I. Anforderungen an Hochschulabsolvierende in Zeiten von Diversität. career services papers. 2018;16:9-21