Bioflocculation production from lower-molecular fatty acids as a novel strategy for utilization of sludge digestion liquor

2001 ◽  
Vol 44 (10) ◽  
pp. 237-243 ◽  
Author(s):  
M. Fujita ◽  
M. Ike ◽  
J.-H. Jang ◽  
S.-M. Kim ◽  
T. Hirao

We propose the bioproduction of a bioflocculant from lower-molecular fatty acids as an innovative strategy for utilizing waste sludge digestion liquor. Fundamental studies on the production, characterization and application of a novel bioflocculant were performed. Citrobacter sp. TKF04 was screened out of 1,564 natural isolates as a bacterial strain capable of a bioflocculant from acetic and propionic acids. TKF04 produced the bioflocculant during the logarithmic growth in the batch cultivation, and it could be recovered from the culture supernatant by ethanol precipitation. The fed-batch cultivation with feeding of acetic acid: ammonium 10;1 (mole) to maintain pH 8.5 led to the hyper-production of the bioflocculant. The bioflocculant was found to be effective for flocculating a kaolin suspension, when added at a final concentration of 1-10 mg/l, over a wide range of pHs (2-8) and temperatures (3-95°C), while the addition of cations was not required. It could flocculate a variety of inorganic and organic suspended particles including kaolin, diatomite, bentonite, activated carbon, soil and activated sludge. These indicated that the bioflocculant possesses flocculating activity comparable or superior to that of synthetic flocculants. The bioflocculation was identified as a chitosan-like biopolymer.

2018 ◽  
Vol 6 (4) ◽  
pp. 1162-1169 ◽  
Author(s):  
Zhijiang Li ◽  
Yanan Zhou ◽  
Hongzhi Yang ◽  
Dongjie Zhang ◽  
Chengtao Wang ◽  
...  

Fermentation ◽  
2021 ◽  
Vol 7 (2) ◽  
pp. 62
Author(s):  
Konstantins Dubencovs ◽  
Janis Liepins ◽  
Arturs Suleiko ◽  
Anastasija Suleiko ◽  
Reinis Vangravs ◽  
...  

The Kluyveromyces marxianus yeast recently has gained considerable attention due to its applicability in high-value-added product manufacturing. In order to intensify the biosynthesis rate of a target product, reaching high biomass concentrations in the reaction medium is mandatory. Fed-batch processes are an attractive and efficient way how to achieve high cell densities. However, depending on the physiology of the particular microbial strain, an optimal media composition should be used to avoid by-product synthesis and, subsequently, a decrease in overall process effi-ciency. Thus, the aim of the present study was to optimise the synthetic growth medium and feeding solution compositions (in terms of carbon, nitrogen, phosphorous, magnesium, and calcium concentrations) for high cell density K. marxianus fed‑batch cultivations. Additionally, the biomass yields from the vitamin mixture and other macro/microelements were identified. A model predictive control algorithm was successfully applied for a fed-batch cultivation control. Biomass growth and substrate consumption kinetics were compared with the mathematical model predictions. Finally, 2‑phenylethanol biosynthesis was induced and its productivity was estimated. The determined optimal macronutrient ratio for K. marxianus biomass growth was identified as C:N:P = 1:0.07:0.011. The maximal attained yeast biomass concentration was close to 70 g·L-1 and the 2-PE biosynthesis rate was 0.372 g·L−1·h−1, with a yield of 74% from 2-phenylalanine.


Viruses ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 660
Author(s):  
Lu Tan ◽  
Yiwen Zhang ◽  
Xingxing Wang ◽  
Dal Young Kim

Most alphaviruses are transmitted by mosquitoes and infect a wide range of insects and vertebrates. However, Eilat virus (EILV) is defective for infecting vertebrate cells at multiple levels of the viral life cycle. This host-restriction property renders EILV an attractive expression platform since it is not infectious for vertebrates and therefore provides a highly advantageous safety profile. Here, we investigated the feasibility of versatile EILV-based expression vectors. By replacing the structural genes of EILV with those of other alphaviruses, we generated seven different chimeras. These chimeras were readily rescued in the original mosquito cells and were able to reach high titers, suggesting that EILV is capable of packaging the structural proteins of different lineages. We also explored the ability of EILV to express authentic antigens via double subgenomic (SG) RNA vectors. Four foreign genetic materials of varied length were introduced into the EILV genome, and the expressed heterologous genetic materials were readily detected in the infected cells. By inserting an additional SG promoter into the chimera genome containing the structural genes of Chikungunya virus (CHIKV), we developed a bivalent vaccine candidate against CHIKV and Zika virus. These data demonstrate the outstanding compatibility of the EILV genome. The produced recombinants can be applied to vaccine and diagnostic tool development, but more investigations are required.


Kybernetes ◽  
2019 ◽  
Vol 48 (7) ◽  
pp. 1463-1477
Author(s):  
Olga Marino ◽  
Jaime Andres Gutierrez ◽  
Sandra Aguirre

Purpose This paper aims to propose and evaluate a pedagogically sound and innovative strategy to teach a higher education course that prepares future professionals to intelligently use information and communication technologies (ICTs) in their personal and professional lives. Design/methodology/approach The conceptual framework used for the design of the course was the socio-constructivism and activity theories. The implementation of the course was evaluated using the intrinsic case study methodology by including several instruments. Findings The pedagogical strategy proposed proved to be sound, as the evaluation showed that students were able to describe, use and propose innovative uses of a wide range of cutting-edge technologies in their both everyday lives and professional settings; they also had the skills to analyse the opportunities and challenges that these presented. Moreover, students liked this innovative way of learning and ended with a positive attitude towards ICT. Originality/value Although several courses prepare students to be digital citizens or use ICT to enhance the teaching-learning process, millennials are ill prepared to use cutting-edge technologies in an innovative, responsible and critical way in their future professions. The course that was designed is original in that it goes beyond preparing digital citizens to prepare professionals in any domain to use ICT in an informed and responsible way. Moreover, it is a documented, successful example of an undergraduate universal course in a highly important current society dimension. The authors believe that its pedagogical proposal could be transferred to courses dealing with other global issues such as the environment, economy and peace.


Foods ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 881
Author(s):  
Roberta Tolve ◽  
Fernanda Galgano ◽  
Nicola Condelli ◽  
Nazarena Cela ◽  
Luigi Lucini ◽  
...  

The nutritional quality of animal products is strongly related to their fatty acid content and composition. Nowadays, attention is paid to the possibility of producing healthier foods of animal origin by intervening in animal feed. In this field, the use of condensed tannins as dietary supplements in animal nutrition is becoming popular due to their wide range of biological effects related, among others, to their ability to modulate the rumen biohydrogenation and biofortify, through the improvement of the fatty acids profile, the derivate food products. Unfortunately, tannins are characterized by strong astringency and low bioavailability. These disadvantages could be overcome through the microencapsulation in protective matrices. With this in mind, the optimal conditions for microencapsulation of a polyphenolic extract rich in condensed tannins by spray drying using a blend of maltodextrin (MD) and gum Arabic (GA) as shell material were investigated. For this purpose, after the extract characterization, through spectrophotometer assays and ultra-high-performance liquid chromatography-quadrupole time-of-flight (UHPLC-QTOF) mass spectrometry, a central composite design (CCD) was employed to investigate the combined effects of core:shell and MD:GA ratio on the microencapsulation process. The results obtained were used to develop second-order polynomial regression models on different responses, namely encapsulation yield, encapsulation efficiency, loading capacity, and tannin content. The formulation characterized by a core:shell ratio of 1.5:5 and MD:GA ratio of 4:6 was selected as the optimized one with a loading capacity of 17.67%, encapsulation efficiency of 76.58%, encapsulation yield of 35.69%, and tannin concentration of 14.46 g/100 g. Moreover, in vitro release under varying pH of the optimized formulation was carried out with results that could improve the use of microencapsulated condensed tannins in animal nutrition for the biofortification of derivates.


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