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Growth optimization of Klebsiella pneumoniae in magnetically assisted bioreactor

Konopacki Maciej, Augustyniak Adrian, Grygorcewicz Bartłomiej, Dołęgowska Barbara, Kordas Marian, Rakoczy Rafał

Chemical and Process Engineering

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2022

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Vol. 43, nr 3

289–-304

EN

In recent years, infections are more often caused by pathogens with high multi-drug resistance, classified as the “ESKAPE” microorganisms. Therefore, investigation of these pathogens, e.g., Klebsiella pneumoniae, often requires biomass production for treatment testing such as antibiotics or bacteriophages. Moreover, K. pneumoniae can be successfully applied as a biocatalyst for other industrial applications, increasing the need for this bacteria biomass. In the current study, we proposed a novel magnetically assisted bioreactor for the cultivation of K. pneumoniae cells in the presence of an external alternating magnetic field (AMF). High efficiency of the production requires optimal bacteria growth conditions, e.g., temperature and field frequency. Therefore, we performed an optimization procedure using a central composite design for these two parameters in a wide range. As an objective function, we utilized a novel, previously described growth factor that considers both biomass and bacteria growth kinetics. Thus, based on the response surface, we could specify the optimal growth conditions. Moreover, we analysed the impact of the AMF on bacteria proliferation, which indicated positive field frequency windows, where the highest stimulatory effect of AMF on bacteria proliferation occurred. Obtained results proved that the magnetically assisted bioreactor could be successfully employed for K. pneumoniae cultivation.

2

Wpływ warunków hodowli na wzrost komórek Bacillus subtilis 4/7 syntetyzujących celulazę

Wita Agnieszka, Białas Wojciech, Wilk Radosław, Szychowska Katarzyna, Czaczyk Katarzyna

Przemysł Chemiczny

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2019

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T. 98, nr 5

742--746

PL

Szczepy Bacillus subtilis mają kilka istotnych cech, które obejmują promocję wzrostu roślin, biokontrolę, solubilizację fosforu oraz produkcję komercyjnych enzymów. Szczególnie ważne są celulazy, enzymy hydrolizujące wiązania β-1,4-D-glikozydowe w cząsteczce celulozy. Zoptymalizowano warunki hodowli okresowej mającej na celu zwiększenie wydajności produkcji biomasy szczepu Bacillus subtilis 4/7. W badaniach wykorzystano pożywkę zawierającą karboksymetylocelulozę jako jedyne źródło węgla. Dzięki optymalizacji procesu hodowli uzyskano 3-krotne zwiększenie stężenia komórek wegetatywnych.

EN

A culture medium (vol. 2 L) based on carboxymethylcellulose and peptone with concns. of 20 g/L and 10 g/L, resp., was used to cultivate the title strain in a bioreactor at 32°C for 48-96 h. A content of O₂ dissolved in the culture medium, its pH and a speed of stirring were changed in the ranges of 0-20%, 6.5-8.5 and 50-800 rpm, resp. The best results were achieved for the process with 20% O₂ content in the culture medium, whose pH was close to 7 and stirred at 50-800 rpm.

3

Determination of volatile organochalcogens using liquid phase microextraction and gas chromatography with fluorine-induced chemiluminescence detection

Hashemi M., Montes R. A., Chasteen T. G.

Environmental Biotechnology

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2012

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Vol. 8, No. 2

55--62

EN

In this study, a simple and rapid liquid phase microextraction technique coupled with gas chromatography and fluorineinduced chemiluminescence detection has been developed for determination of volatile organochalcogens (dimethyl sulfide, dimethyl disulfide, dimethyl trisulfide and dimethyl diselenide and dimethyl telluride). The effects of extraction parameters such as extracting solvent and its volume, stirring time extraction time and salt effect were optimized. Also, analytical figures of merit such as response linearity, repeatability and reproducibility, and limits of detection have been evaluated. The proposed method was found to be a simple and rapid analytical procedure for determination of volatile organochalcogens in real aqueous samples with detection limits of 5-620ng·l-1. The relative recoveries of these analytes for spiked bacterial cultures, tap water and lake water ranged from 95 to 105% with the relative standard deviations of 0.3-11.0%.

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Skomputeryzowany system sterowania hodowlą bakterii aerobowych w fermentorze

Trzmiel T.

Zeszyty Naukowe. Chemia Spożywcza i Biotechnologia / Politechnika Łódzka

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2001

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Z. 65

79-90

PL

W pracy przedstawiono opis budowy i działania skomputeryzowanego systemu sterowania pracą fermentora, który opracowano w Instytucie Biochemii Technicznej oraz na przykładzie biosyntezy subtilizyny przez bakterie B.subtilis IBTC-3 pokazano jego możliwości.

EN

Construction and basis work of the Computerizing System Steering of Fermentor (SSSF), mounting in Institute of Biochemistry Technical University Łódź were described. The results of biosynthesis of subtilisin by Bacillus subtilis IBTC-3 in SSSF were also described.