Carbon monoxide conversion with Clostridium aceticum.

Carbon monoxide concentrations in syngas are often high, but tolerance toward CO varies a lot between homoacetogenic bacteria. Analysis of the autotrophic potential revealed that the first isolated acetogenic bacterium Clostridium aceticum was able to use CO as sole carbon and energy source for chemolithoautotrophic carbon fixation but simultaneously showed little tolerance to high CO concentrations. Not yet reported, autotrophic ethanol production by C. aceticum was discovered with CO as a substrate in batch processes. Growth rates estimated in batch processes at varying CO partial pressures were used to identify the CO inhibition kinetics of C. aceticum, using a substrate inhibition model. C. aceticum shows a strong CO inhibition with an optimum CO partial pressure of only 5.4 mbar in the gas phase at cell dry weight concentrations of up to 0.5 g·L -1 . At optimum conditions, growth and acetate formation rates were estimated to be 0.24 hr -1 and 0.52 g·g -1 ·hr -1 , respectively. Syngas fermentation at high partial pressures of up to 280 mbar CO in the inlet gas phase was enabled by applying a continuously operated stirred-tank bioreactor with submerged membranes with total cell retention. Around 70% CO conversion was achieved continuously in the membrane bioreactor with strongly CO inhibited C. aceticum resulting in space-time yields of up to 0.85 g·L -1 ·hr -1 acetate.

Why are young adults affected? Estimating measles vaccination coverage in 20-34 year old germans in order to verify progress towards measles elimination.

BACKGROUND: The introduction of measles vaccination into routine childhood vaccination programmes has led to a shift of disease burden and incidence among young adults. This was confirmed by the recent rise in measles cases and outbreaks throughout Europe. To prevent outbreaks and eliminate measles, one of the key objectives of the WHO Europe measles elimination framework is achieving overall vaccination coverage of ≥95% in the population on a district level. In the absence of national registers, data on vaccination coverage in Germany is recorded at the age of school entry, through insurance refund claim data and population studies. Vaccination status (VS) of young adults is largely unknown. METHODS: We assessed measles vaccination coverage in young adults aged 20-34 years on a district level of the German Federal State of Rhineland-Palatinate. The knowledge and attitude towards immunization of unvaccinated to vaccinated young adults were compared using Likert questions. We used proportional allocation for stratified random sampling across 36 counties. We mailed a self-administered questionnaire with pre-paid return envelopes along with an offer to complete online. Prior to calculating coverage we tested for non-responder bias using logistic regression. RESULTS: 465 (28%) of 1,637 persons contacted responded (mail: 23%, online: 5%). More women responded than men (odds ratio (OR)=2.1; 95% confidence intervall (CI)=1.7-2.6) but age did not vary between responders and non-responders. Vaccination coverage was 90% (95%CI=87%-93%) for one and 56% (95%CI=51%-61%) for two doses. We found a statistically significant association between receiving two doses and age group. The 20-24 years age group had a 2.3 higher incidence rate ratio (95%CI=1.7-3.2) than the reference group of 30-34 year old to have received two doses of measles vaccination. The group of 25-29 year old had a 1.5 higher incidence rate (95%CI=1.0-2.1) than the reference group to have received two doses of measles vaccination. CONCLUSIONS: Coverage has failed to reach the WHO Europe elimination goal of 95% measles vaccination in the general population. Targeted approaches including enlistment of occupational health services and checking vaccination status during general practitioner (GP) visits are needed to increase vaccination uptake in this age group in order to achieve measles elimination.