Taking the TU Delft Carpentries Workshops Online

Due to the COVID-19 pandemic, Delft University of Technology in the Netherlands (TU Delft) stopped its activities on campus until autumn 2021 and moved all teaching activities to an online setting. This article describes the challenges and lessons learned from successfully moving basic programming workshops, Software Carpentry workshops, online. The article details the local TU Delft context, the online workshop tools that were employed, and the roles that the organising team played to organise and run these online workshops. To successfully adapt to the online context, it was important to adjust the original planning and programme for the Carpentry workshops. General challenges of online workshops and solutions that worked for the TU Delft team are also shared. Through iteratively developing the online workshops over the past year, the team has enhanced both learners’ and organisers’ experience. The lessons learned will continue to be valuable when the workshops are transitioned back to a physical setting when COVID-19 protective measures are lifted

<i>Delftia</i> sp LCW, a strain isolated from a constructed wetland shows novel properties for dimethylphenol isomers degradation

BACKGROUND: Dimethylphenols (DMP) are toxic compounds with high environmental mobility in water and one of the main constituents of effluents from petro- and carbochemical industry. Over the last few decades, the use of constructed wetlands (CW) has been extended from domestic to industrial wastewater treatments, including petro-carbochemical effluents. In these systems, the main role during the transformation and mineralization of organic pollutants is played by microorganisms. Therefore, understanding the bacterial degradation processes of isolated strains from CWs is an important approach to further improvements of biodegradation processes in these treatment systems. RESULTS: In this study, bacterial isolation from a pilot scale constructed wetland fed with phenols led to the identification of Delftia sp. LCW as a DMP degrading strain. The strain was able to use the o-xylenols 3,4-DMP and 2,3-DMP as sole carbon and energy sources. In addition, 3,4-DMP provided as a co-substrate had an effect on the transformation of other four DMP isomers. Based on the detection of the genes, proteins, and the inferred phylogenetic relationships of the detected genes with other reported functional proteins, we found that the phenol hydroxylase of Delftia sp. LCW is induced by 3,4-DMP and it is responsible for the first oxidation of the aromatic ring of 3,4-, 2,3-, 2,4-, 2,5- and 3,5-DMP. The enzyme may also catalyze both monooxygenation reactions during the degradation of benzene. Proteome data led to the identification of catechol meta cleavage pathway enzymes during the growth on ortho DMP, and validated that cleavage of the aromatic rings of 2,5- and 3,5-DMPs does not result in mineralization. In addition, the tolerance of the strain to high concentrations of DMP, especially to 3,4-DMP was higher than that of other reported microorganisms from activated sludge treating phenols. CONCLUSIONS: LCW strain was able to degraded complex aromatics compounds. DMPs and benzene are reported for the first time to be degraded by a member of Delftia genus. In addition, LCW degraded DMPs with a first oxidation of the aromatic rings by a phenol hydroxylase, followed by a further meta cleavage pathway. The higher resistance to DMP toxicity, the ability to degrade and transform DMP isomers and the origin as a rhizosphere bacterium from wastewater systems, make LCW a suitable candidate to be used in bioremediation of complex DMP mixtures in CWs systems

Neighbor joining tree of BssA amino acidic sequences.

<p>The cluster shown as a triangle represents members of a clone library obtained from a PFR closely related to <i>Magnetospirillum</i> strain TS-6 and to the isolate 15–1. Clones 57 and 78 are part of a second subgroup and C54 is shown in the <i>Thauera</i> cluster</p

Microscopy observation of strain 15–1 isolated from a Planted Fixed-bed Reactor (PFR).

<p>Microscopy observation of strain 15–1 isolated from a Planted Fixed-bed Reactor (PFR).</p

Effect of toluene on growth (closed circles) and degree of saturation of membrane fatty acids (open squares) of strain 15–1.

<p>Effect of toluene on growth (closed circles) and degree of saturation of membrane fatty acids (open squares) of strain 15–1.</p

Anaerobic and aerobic growth tests of denitrifying strain 15–1 with different aromatic and non-aromatic compounds as sole carbon sources.

<p>Anaerobic and aerobic growth tests of denitrifying strain 15–1 with different aromatic and non-aromatic compounds as sole carbon sources.</p