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The ethanol concentration in batch cultivation with the yeast Saccharomyces cerevisiae was predicted on-line using a gas sensor array. Headspace samples were pumped past the gas sensors array for 10 s every five minutes and the voltage changes of the sensors were measured. For the calibration procedure no off-line sampling was used. Instead, a theoretical model of the process has been applied to simulate the ethanol production at any given time. However, the kinetic parameters of the simulation model are unknown at the beginning of the calibration. It is demonstrated that these kinetic parameters of the theoretical process model can be acquired from the response of the gas sensor array alone. The calculated parameters result in a simulation model that is at least as accurate as a model whose parameters have been acquired by least squares fitting to off-line measurements. The root mean square error of calibration as well as the percentage error for validation sets were below 0.2 g L−1 and 7%, respectively. The obtained results indicate that the model-based calibrated gas sensor array can be a cheap alternative to other tools, such as spectroscopy-based methods, that are used for monitoring yeast cultivations.

Many recent studies have been conducted to find new DNA vaccines based on Toxoplasma gondii antigens. DNA vaccines encoding complex of different antigens showed better immune responses compared to single antigen vaccine. In this study, we constructed a DNA vaccine encoding SAG1, SAG3, MIC4, GRA5, GRA7, AMA1 and BAG1 against T. gondii, and evaluated the immune response it induced in BALB/c mice. For this purposes, thirty BALB/c mice were randomly divided into three groups containing tenmice each. There were two negative control groups (PBSand pVAX1 vector) and one vaccination group (pVAX1-MAF, Multantigenic Fragment). On days 0, 14 and 28, the mice were immunized intramuscularly, and 5 weeks later they were challenged with T. gondii RH strain. The immune responses were evaluated using lymphocyte proliferation assay, T-cell subsets detection, and measurement of antibody and cytokine levels. The results showed that mice immunized with pVAX1-MAF developed high levels of IL-2, IL-12, IgG and IFN- γ as well as CD3

A fuzzy logic control system is designed and applied to a proofing system. The controller is experimentally evaluated and the performance is compared to the ones from a PID controller. Dough pieces with different amounts of yeast added in the ingredients and in different temperature starting states are prepared and proofed with the supervision of the fuzzy control system. The controller is designed to maintain the volume of the dough pieces similar to volume expansion of a dough piece in standard conditions during the proofing process. Controllers are evaluated by means of performance criteria and the final volume of the dough samples. It is demonstrated that the fuzzy logic controller can provide significant better control, does not require a mathematical model and has better disturbance rejection properties.

The Resilient Slip Friction Joint (RSFJ) has recently been developed and introduced to the construction industry. This joint is a friction-based energy dissipation device that owing to its special configuration can provide energy absorption and self-centring behaviour in one package. This device is most applicable when the designers consider a damage avoidance philosophy of design. One of the applications of this device is the RSFJ brace. In this bracing system, the required seismic performance is provided by the RSFJ and the rest of the brace components are aimed to stay elastic. This paper introduces the RSFJ bracing system including the collapse-prevention fuse. This built-in fuse works in a way that when the applied force exceeds the design load, the secondary fuse is activated and the RSFJ brace is still able to provide self-centring up to twice the target deformation with an axial force of up to 1.25 times of the target design force. The performance of this fuse is investigated by experimental tests on the component level and the results are presented. Moreover, a numerical model for a five story steel structure with RSFJ braces is developed and was subjected to non-linear static pushover and nonlinear dynamic time-history simulations in order to investigate the seismic performance of the proposed system. The findings of this research shows that the RSFJ brace system can offer substantial performance benefits and has the merit to be considered as an efficient alternative for the current bracing systems.

Since more than twenty years ago, some species of bacteria and fungi have been used to produce protein biomass or single-cell protein (SCP), with inexpensive feedstock and wastes being used as their sources of carbon and energy. The role of SCP as a safe food and feed is being highlighted more because of the worldwide protein scarcity. Even though SCP has been successfully commercialized in the UK for decades, study of optimal fermentation conditions, various potential substrates, and a broad range of microorganisms is still being pursued by many researchers. In this article, commonly used methods for the production of SCP and different fermentation systems are briefly reviewed, with submerged fermentation being highlighted as a more commonly used method. Emphasis is given to the effect of influencing factors on the biomass yield and productivity in an effort to provide a comprehensive review for researchers in related fields of interest.How to cite: Reihani SFS, Khosravi-Darani K. Influencing factors on single cell protein production by submerged fermentation: A review. Electron J Biotechnol 2019;37. https://doi.org/10.1016/j.ejbt.2018.11.005. Keywords: Aeration, Agricultural waste, Algae, Bacteria, Biomass, Fermentation condition, Fungi, Population growth, Poverty, Protein demand, Single-cell protein, Submerged fermentation

A major obstacle in the utilization of phenolic antioxidant compounds is their sensitivity and as a result stability issue. The current study aimed to encapsulate polyphenolic compounds, extracted from Rosemary, in liposomes prepared by the Mozafari method without the utilization of toxic solvents or detergents. The extract was prepared and converted into a powder by freeze-drying. The encapsulation protocol was optimized by changing the main process variables (i.e. liposomal ingredients, process temperature, and time). Results demonstrated that to achieve the highest rate of encapsulation, the best concentration of phosphatidylcholine (PC) and the extract were ca. 2.5% and 0.7% (w/w) respectively. The optimum process temperature and time were 70°C and 60 minutes respectively. It can be concluded that the liposomal rosemary extract formulation prepared in this study, employing a safe, scalable, and green technology, has great promise in food and pharmaceutical applications.

In this study, stability of yeast-metal complexes under simulated gastrointestinal condition, isotherm and kinetic models of absorptions, and the effects of pretreatments on biosorption has been studied. Results showed that the best biosorption of metals from aqueous solutions by Saccharomyces (S.) cerevisiae may be achieved after NaOH pretreatment for Mercury (Hg) 90.6%. While biodecontamination of Lead (Pb) 37.48%, Arsenic (As) 19.44%, and Cadmium (Cd) 39.9% by untreated yeast was better. In gastrointestinal condition Hg and Cd-yeast complexes were more stable and biosorption of Cd and Pb increased. Bonds of As and Hg-yeast complexes in digestion condition be reversible. The metals biosorption by untreated yeast followed the pseudo-second-order kinetic and The Langmuir isotherm models for all metals (As matched with Langmuir and Freundlich). In conclusion, using S. cerevisiae to limit the bioavailability of heavy metals in fermented drinking and dairy after digestion condition cannot be safe and metal-yeast bonds are reversible.