Abstract Levoglucosan is a promising sugar present in the lignocellulose pyrolysis bio-oil, which is a renewable and environment-friendly source for various value-added productions. Although many microbial catalysts have been engineered to produce biofuels and chemicals from levoglucosan, the demerits that these biocatalysts can only utilize pure levoglucosan while inhibited by the inhibitors co-existing with levoglucosan in the bio-oil have greatly limited the industrial-scale application of these biocatalysts in lignocellulose biorefinery. In this study, the previously engineered Escherichia coli LGE2 was evolved for enhanced inhibitor tolerance using long-term adaptive evolution under the stress of multiple inhibitors and finally, a stable mutant E. coli -H was obtained after ~ 374 generations’ evolution. In the bio-oil media with an extremely acidic pH of 3.1, E. coli -H with high inhibitor tolerance exhibited remarkable levoglucosan consumption and ethanol production abilities comparable to the control, while the growth of the non-evolved strain was completely blocked even when the pH was adjusted to 7.0. Finally, 8.4 g/L ethanol was achieved by E. coli -H in the undetoxified bio-oil media with ~ 2.0% (w/v) levoglucosan, reaching 82% of the theoretical yield. Whole-genome re-sequencing to monitor the acquisition of mutations identified 4 new mutations within the globally regulatory genes rssB , yqhA , and basR, and the − 10 box of the putative promoter of yqhD - dgkA operon. Especially, yqhA was the first time to be revealed as a gene responsible for inhibitor tolerance. The mutations were all responsible for improved fitness, while basR mutation greatly contributed to the fitness improvement of E. coli -H. This study, for the first time, generated an inhibitor-tolerant levoglucosan-utilizing strain that could produce cost-effective bioethanol from the toxic bio-oil without detoxification process, and provided important experimental evidence and valuable genetic/proteinic information for the development of other robust microbial platforms involved in lignocellulose biorefining processes.
Rift Valley fever (RVF) is an emerging zoonotic mosquito-borne disease caused by Rift Valley Fever virus (RVFV), affecting both humans and animals. It is endemic to Rwanda and Tanzania and Uganda which are adjacent countries, with possible transboundary transmissions. Despite the various outbreak reports in Rwanda since 2012, information on the intensity and spread of these outbreaks and their management is scarce. We describe the 2022 outbreak that happened in Rwanda and provide insights into the One Health response implemented during the outbreak. There were no human cases officially reported. A total of 1339 confirmed RVF animal cases were identified from 21 March until 31 December 2022. The breakdown of the cases per livestock species showed 1285 (96%) cases in cattle, 34 (3%) in goats and 20 (1%) in sheep. Of the confirmed livestock cases, 516 died and 1254 abortions were registered, in all affected species. The outbreak response was characterized by extensive interventions such as animal spraying with pyrethroid insecticides, vaccinations, and active follow-up of animals and humans in the households with animal cases. In the first phase of the outbreak, animal movements and slaughtering were restricted in the highly affected regions. Gradually, the abattoir slaughter activities were resumed with all animals required to test negative by RT-PCR before slaughter. Remarkably, the public services and hospital laboratories supported both capacity building of veterinary laboratory scientists and testing of animals' samples. The overall response was coordinated by district cross-sectoral teams linking national and community-level actors. Outbreak-related information was synthesized by the district teams and shared at national level while national strategies were communicated to the affected communities through the district structures. Rwanda's response to RVF provides a proof of concept that multisectoral efforts involving community members in a One Health approach can offer efficient response to zoonotic outbreaks while still protecting the country's economy.
'/%3e%3cuse xlink:href='%23a' transform='rotate(23.036 .093 25.536)'/%3e%3cuse xlink:href='%23a' transform='rotate(45.87 1.273 16.18)'/%3e%3cuse xlink:href='%23a' transform='rotate(69.945 .996 12.078)'/%3e%3cuse xlink:href='%23a' transform='rotate(20.66 -19.689 31.932)'/%3e%3c/svg%3e)
'%3e%3cg id='b'%3e%3cpath id='a' fill='%23E5BE01' d='M116.1 0 35.692 4.699l76.452 25.35L33.26 13.777l67.286 44.273L28.56 21.915l53.534 60.18-60.18-53.534 36.135 71.985L13.777 33.26l16.272 78.884-25.35-76.452L0 116.1-1-1z'/%3e%3cuse xlink:href='%23a' transform='scale(1 -1)'/%3e%3c/g%3e%3cuse xlink:href='%23b' transform='scale(-1 1)'/%3e%3ccircle r='34.3' fill='%23E5BE01' stroke='%2300A1DE' stroke-width='3.4'/%3e%3c/g%3e%3c/svg%3e)
