Parallel use of shake flask and microtiter plate online measuring devices (RAMOS and BioLector) reduces the number of experiments in laboratory-scale stirred tank bioreactors

Background Conventional experiments in small scale are often performed in a Black Box fashion, analyzing only the product concentration in the final sample. Online monitoring of relevant process characteristics and parameters such as substrate limitation, product inhibition and oxygen supply is lacking. Therefore, fully equipped laboratory-scale stirred tank bioreactors are hitherto required for detailed studies of new microbial systems. However, they are too spacious, laborious and expensive to be operated in larger number in parallel. Thus, the aim of this study is to present a new experimental approach to obtain dense quantitative process information by parallel use of two small-scale culture systems with online monitoring capabilities: Respiration Activity MOnitoring System (RAMOS) and the BioLector device. Results The same mastermix (medium plus microorganisms) was distributed to the different small-scale culture systems: 1) RAMOS device; 2) 48-well microtiter plate for BioLector device; and 3) separate shake flasks or microtiter plates for offline sampling. By adjusting the same maximum oxygen transfer capacity (OTRmax), the results from the RAMOS and BioLector online monitoring systems supplemented each other very well for all studied microbial systems (E. coli, G. oxydans, K. lactis) and culture conditions (oxygen limitation, diauxic growth, auto-induction, buffer effects). Conclusions The parallel use of RAMOS and BioLector devices is a suitable and fast approach to gain comprehensive quantitative data about growth and production behavior of the evaluated microorganisms. These acquired data largely reduce the necessary number of experiments in laboratory-scale stirred tank bioreactors for basic process development. Thus, much more quantitative information is obtained in parallel in shorter time.Cluster of Excellence “Tailor-Made Fuels from Biomass”, which is funded by the Excellence Initiative by the German federal and state governments to promote science and research at German universities

Two new species of Platynereis (Polychaeta : Nerreididae) from eastern Mexican shores

Two new species of Platynereis are described from Mexican shores, P. hutchingsae, new species and P. mucronata, new species. These species differ from others in the genus mainly by the disposition and shape of the setae

The Effect of Aeration for 6-Pentyl-alpha-pyrone, Conidia and Lytic Enzymes Production by Trichoderma asperellum Strains Grown in Solid-State Fermentation

International audienceIn recent years, the production of biopesticides has gained great attention in the scientific word because it is an important alternative to replace the much debated chemical pesticides used on the field crops. Fungal lytic enzymes, conidia and secondary metabolites like 6 pentyl-alpha-pyrone (6-PP) play a very important role in the biological control of pests. On the present study, the influence of application of air through a solid-state fermentation using three Trichoderma asperellum strains to produce conidia, 6-PP and essential enzymes were evaluated. A mix of vine shoots, potatoes flour, jatropha, olive pomace and olive oil as substrates was used. T. asperellum TV104 showed the best 6-PP production (3.06 ± 0.15 mg g DM−1), cellulases activities (34.3 ± 0.4 U g−1), and amylase activity (46.3 ± 0.6 U g−1) however, T. asperellum TF1 produced the higher levels of lipase (30.6 ± 0.3 U g−1), under air conditions. The production of these same enzymes was less efficient without the application of forced aeration. The forced aeration increased the conidia production, the best value was observed with T. asperellum TF1 (2.23 ± 0.07 × 109 g DM−1)

Aroma compounds production by solid state fermentation, importance of in situ gas-phase recovery systems

International audienceFlavour and fragrance compounds are extremely important for food, feed, cosmetic and pharmaceutical industries. In the last decades, due to the consumer's increased trend towards natural products, a great interest in natural aroma compounds has arisen to the detriment of chemically synthesised ones. Recently, solid state fermentation (SSF) has been applied in the production of many metabolites. Aroma compounds can be produced by SSF with a higher yield compared to submerged fermentation (SmF). In SSF processes, aroma compounds can be produced in the solid matrix or in the headspace, but they can be lost or stripped when aeration is required. This review focuses on the production of aroma compounds by SSF processes with a special highlight on in situ systems to recover the volatiles released in the gaseous phase and stripped due to aeration. Following a brief presentation of specificities of SSF processes concerning the choice of microorganisms and the solid matrix used for the production of aroma compounds, bioreactor aspects, factors affecting production of aroma compounds and in situ gas phase aroma recovery systems in aerated SSF bioreactors are discussed