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The production of fungal metabolites and conidia at an industrial scale requires an adequate yield at relatively low cost. To this end, many factors are examined and the design of the bioreactor to be used for the selected product takes a predominant place in the analysis. One approach to addressing the issue is to integrate the scaling-up procedure according to the biological characteristics of the microorganism considered, i.e. in our case filamentous fungi. Indeed, the scaling-up procedure is considered as one of the major bottlenecks in fermentation technology, mainly due to the near impossibility of reproducing the ideal conditions obtained in small reactors designed for research purposes when transposing them to a much larger production scale. The present review seeks to make the point regarding the bioreactor design and its implementation for cultivation of filamentous fungi and the production of fungal metabolites according to different developmental stages of fungi of industrial interest. Solid-state (semi-solid), submerged, fermentation and biofilm reactors are analyzed. The different bioreactor designs used for these three processes are also described at the technological level.

Overview of current knowledge on management of hydrocarbon pollution in mangroves. Mangrove forests are vital in terms of biomass production and maintenance of the natural balance in coastal areas in the tropics. However, mangroves are subject to pollution from human activities. Oil pollution is one of the causes leading to the decline of mangroves, which represent only 1% of the area of all the world's tropical forests. Several techniques are available for the remediation of oil contaminated areas. Biodegradation appears to be the best suited to mangrove ecosystems. However this technique remains confined to the laboratory. Field tests in situ need to be conducted in order to evaluate the results obtained in the laboratory.

The development of mini- and micro-cultivation devices allows the optimization of bioprocesses to be speeded up, as well as a better understanding of microbial physiology under process conditions. Mini-bioreactors have been specifically developed for the parallel cultivation of microorganisms under process-representative conditions. These scaled-down models of industrial bioreactors can easily be multiplied to perform high-throughput studies. Micro-cultivation devices have also been designed to obtain deeper insight on the level of microbial physiology. More specifically, single-cell micro-cultivation devices have been developed to study the impact of microbial phenotypic heterogeneity on bioprocesses.

Phosphate rock has long been used for the production of phosphorus based chemicals. However, considering the depletion of the reservoirs and the decrease of the quality of phosphate rocks, a potential market is now emerging for the recovery of phosphate from waste and its reuse for different applications. Notably, phosphate recovery from wastewater could be included in a circular economy approach. This review focuses on the use of microbial systems for phosphorus accumulation and recovery, by considering the actual range of analytical techniques available for the monitoring of phosphorus accumulating organisms, as well as the actual biochemical and metabolic engineering toolbox available for the optimization of bioprocesses. In this context, knowledge gathered from process, system and synthetic biology could potentially lead to innovative process design.

Bioreactor scale-up and design on the basis of physiologically relevant parameters: application to the production of lipase by Yarrowia lipolytica. Bioreactor scale-up often poses a serious issue during the industrial development of a bioprocess considering the numerous physical and biological phenomena occurring in the reacting volume. The basic principles of scale-up coming from the traditional chemical and process engineering approaches will be first reviewed and will be then compared to a new one involving recent development at the level of microbial strain manipulation. This "physiological" approach of scale-up involves directly a biological component of the system (by comparison with the traditional approach for scaling-up involving physical parameters indirectly linked to the physiological phenomena occurring in the bioreactor), i.e. the synthesis of a reporter fluorescent protein when microbial cells are exposed to stress. It will be shown how this principle can be used for a better understanding of the relationship between bioreactor hydrodynamics and microbial stress.

Among hemicellulases, xylanases are catalysts of considerable interest so as fundamental than applied point of view. However,it is paradoxical to note that the high cost of their production limits their use on a large scale. The use of purified xylan as culturesubstrate increases the production cost of the enzyme. Consequently, for commercial applications, it is advisable to developprocesses starting from inexpensive substrates. The purpose of this study is to optimise xylanases production in solid-statefermentation based on agricultural residues. The strain is Penicillium canescens 10-10c, selected in our laboratory for his abilityto produce xylanase activity free of cellulase. Assays concern optimization of different culture parameters in order to developin the future a solid-state fermentation reactor with soya oil cake. These parameters are: medium composition, temperatureincubation, induction and repression mechanisms. Soya oil cake in pellets (size > 10 mm) gave a higher enzymatic activity.Great volume of culture medium reduced the enzymatic production. The presence of lactose, saccharose or starch of corn hasa positive effect on the production of xylanase while the presence of xylose, mannose, galactose, arabinose, cellobiose andpectin or methylcellulose reduces the production of xylanase. The sources of phosphorus (di-potassic and di-sodic) enhancexylanase production. The enzymatic production obtained in Erlenmeyer flasks (250 ml) after 7 days incubation at 30°C isabout 14 000 U.g-1 of carbon source. The nature of inoculum affects the enzymatic productivity. Indeed, better productivitywas obtained with inoculation by solid preculture (956 U.g-1 per day) than liquid preculture (473 U.g-1 per day) and sporessuspension (383 U.g-1 per day). These observed enzymatic activity levels are higher than those related in the literature, whichshows all the potentialities of this strain and this technique for the production of xylanase and allow to develop our solid-statefermentation bioreactor.

Introduction. Over the centuries, bio-sourced compounds isolated from plants, insects and microorganisms have been a potent source of drugs for the treatment of human diseases. Literature. Bio-sourced extracts offer a wide diversity of compounds with a large number of potentially beneficial effects in humans. Serendipity has frequently played a key role in the discovery of new medicines. The canonical discovery of penicillin required both chance and a prepared mind to understand and exploit its potential for the treatment of human infections. Nowadays, most anti-cancer drugs currently in clinical use were at least partly discovered by a “fortunate happenstance”. Conclusions. In this review, we recapitulate the story of one of these compounds, 2-propylpentanoic acid, derived from the Valeriana officinalis flowering plant and its path to validation as a cancer treatment., De la valériane au traitement du cancer : le succès d’un composé biosourcé Introduction. Depuis plusieurs siècles, des composés extraits de plantes, d’insectes ou de micro-organismes ont été utilisés comme remèdes pour soigner diverses maladies humaines. Littérature. Les substances naturelles peuvent être à l\'origine de composés ayant des effets bénéfiques sur la santé humaine. De manière surprenante, la sérendipité a fréquemment joué un rôle majeur dans le développement de nouveaux médicaments. Par exemple, la découverte de la pénicilline par Fleming a nécessité une combinaison de chance, de curiosité et d’intuition permettant son exploitation dans le traitement des maladies infectieuses. De plus, plusieurs agents anti-cancéreux couramment utilisés en clinique ont été mis en évidence suite à un heureux concours de circonstances. Conclusions. Cette revue met en relief les différentes étapes ayant permis le développement de l’acide 2-propylpentanoïque à partir de la valériane jusqu\'à son utilisation dans le traitement contre le cancer.

Heterogeneities caused by deficient mixing in large-scale bioreactors have been identified and described in literature. These heterogeneities affect physiological changes of microorganisms through its passage in different zones of concentrations. Consequently the differences in terms of productivities, qualities and/or yields of products of interest have been observed during scaling-up from laboratory to larger scales. For this reason, large-scale process improvement depends on the understanding of dynamic interactions between microbial responses and physical phenomena inside bioreactors. The dynamic responses of microorganisms are used as a tool for gaining insight into the fundamentals of microbial changes under a mixing-well controlled environment. Our research group has not only applied scale-down methodology to study the microbial responses at molecular, microscopic and macroscopic levels of observation, but also has used innovative strains and process engineering tools to evaluate fast dynamic responses of microorganism at time scales from seconds to minutes. This presentation focuses on the application of rational strategies in order to characterize distributed relaxation times of microorganisms which are considered to be constant at all fermentation scales. Experiments were conducted with reporter bioluminescent strains of Escherichia coli in which the luxCDABE operon was fused to promoters responding to different selected environmental stresses (dissolved oxygen, pH, temperature and substrate, etc.). Such strains allow real-time recording of the expression of genes involved in stress responses. Kinetic analyses of biomass, extracellular metabolites, inlet/exhaust gas, were carried out in order to determine mass balances and biological kinetic parameters. We will present our approach and the results concerning continuous culture of E. coli DPD2417 (nirB::luxCDABE) to monitor the microbial responses to oxygen limitation.