Optimization of Large-Scale Culture Conditions for the Production of Cordycepin with<i>Cordyceps militaris</i>by Liquid Static Culture

Borišev

et al. 2020

Sci Rep

the impact of fullerene c 60 water soluble daughter molecules-fullerols c 60 (oH) 24 nanoparticles (fnp) on emerging (non-aflatoxin biosynthetic pathway) toxins production in mycelia and yeast extract sucrose (YeS) media of A. flavus was investigated under growth conditions of 29 °C in the dark for a 168 h period. The FNP solution (10, 100 and 1000 ng mL −1) contained predominantly nanoparticles of 8 nm diameter and with zeta potential mean value of −33 mV. Ten emerging metabolites were produced at concentrations reaching 1,745,035 ng 50 mL −1 YES medium. Seven of the metabolites were found in mycelia and media, while three were only in mycelia. Majority of the metabolites were detected in higher quantity in mycelia than in media, at a ratio of 99:1 (m/m). However, higher metabolite quantities were found in media following FNP application, while FNP caused a decrease of total metabolite quantities in mycelia. The concentrations of the metabolites in media increased in the presence of 1000 ng mL −1 fnp while mycelial quantities of the metabolites decreased with increased applied FNP dose. The impacts of global climate changes on FNP availability in the environment and on mycotoxin occurrence in crops increase the relevance of this study for risk assessment of nanoparticles. Cordycepin is reported for the first time as metabolite of A. flavus. Global climate changes contribute to increased mycotoxin contamination of foods by shaping the mycotoxigenic fungal community structure in the environment. The most obvious example is the prediction of Battiliani et al. 1 about aflatoxins becoming a food safety issue in Eastern Europe, the Balkan Peninsula and Mediterranean regions in the next 100 years as a result of +2 °C environmental temperature change. Several review papers on the impacts of interacting climate change factors on growth and mycotoxin production by major foodborne fungi have been published 2-8. The most important mycotoxigenic fungi is Aspergillus flavus, producer of the strongest known natural hepatocarcinogen-aflatoxin B 1 (AFT B 1). This fungus has been widely studied due to the severe health and economic challenges it causes through aflatoxin contamination of foods. The dynamics of A. flavus, influenced by factors of global climate changes (e.g. temperature, drought stress and CO 2 concentration) have also been recently studied 2,9,10. Besides the regulated mycotoxins, the impact of climate change on the emerging toxins are receiving increasing attention in recent years 2,11. According to Kovalsky et al. 11 emerging toxins are a group of chemically diverse mycotoxins for which to date no regulations exist. For example, the AFT precursors are one of the emerging toxins group 11,12 and there is only limited literature available on the emerging toxins from Aspergillus

Section: Resultsmentioning

confidence: 99%

Impact of fullerol C60(OH)24 nanoparticles on the production of emerging toxins by Aspergillus flavus

Borišev

et al. 2020

Sci Rep

“…Increased mycelial growth increased cordycepin production in the liquid surface culture. On the other hand, even though C. militaris cells are cultivated in a submerged culture with sufficient oxygen supply, cordycepin production was less than that cultivated in a liquid surface culture [18,19]. It suggests that moderate amount of oxygen and less mycelial damage are required for the cordycepin production in C. militaris.…”

Section: Effect Of Ssa On Cordycepin Production In Liquid Surface Culmentioning

confidence: 94%

“…Cordycepin has adenine structure in itself, indicating that adenine may be a precursor of cordycepin. In fact, several researchers reported that the addition of adenine adenosine in the surface culture of C. militaris improved the cordycepin production [15,18].…”

Section: Effect Of An Additive On Cordycepin Productionmentioning

confidence: 99%

Improved cordycepin production in a liquid surface culture of Cordyceps militaris isolated from wild strain

Sari

Suparmin

Kato

et al. 2016

Biotechnol Bioproc E

A Cordyceps militaris NBRC 10352-3 strain that was isolated from C. militaris NBRC10352 produced 68 mg of cordycepin from 100 ml of medium, which was the highest level of cordycepin among 60 isolates from three C. militaris (NBRC 9787, 100741 and 103752) strains. Interestingly, a liquid surface culture of C. militaris NBRC 103752-3 produced 2-fold cordycepin to that in a submerged culture. Cordycepin production was significantly affected by specific surface area (SSA) in the liquid surface culture, and 120.9 mg of cordycepin was produced on SSA of 1.57 cm-1 (from 50 ml). The addition of glycine and adenine as an additive to its culture medium was optimized by an experimental design. When 6.75 g/l of adenine was added to the culture, 315.7 mg of cordycepin was produced from 50 ml medium, improving the cordycepin production by 4.7-fold. In this study, the production and productivity of cordycepin were significantly improved in C. militaris wild type by a single cell colony isolation and additives without adopting any mutational technologies. This C. militaris NBRC 10352-3 strain can be used as a new cordycepin-hyperproducing one, instead of a cordycepinhyperproducing mutant.

“…Bacterial suspensions were inoculated on 50 mL LB liquid medium and cultured in a shaker incubator. The range of fermentation conditions (the influencing factors and levels) was selected as follows: the fermentation time (20,30,40,50, and 60 h), temperature (20,25,30,35, and 40 • C), the inoculum level (0.5%, 1%, 1.5%, 2.0%, and 2.5%), the shaker rotation speed (110, 120, 130, 140, and 150 rpm), and pH (5, 6, 7, 8, and 9) [21,22].…”

Section: Fermentation Experimentsmentioning

confidence: 99%

Optimization of Culture Conditions for Amoxicillin Degrading Bacteria Screened from Pig Manure

Yang

Guo

et al. 2020

IJERPH

(1) Objective: The objective of this study was to screen amoxicillin (AMX)-degrading bacterial strains in pig manure and optimize the fermentation conditions for these strains to achieve high fermentation rate, which can provide an effective way for the practical application of bacterial strains as antibiotic-degrading bacterial in treating livestock waste for antibiotic residues. (2) Methods: Antibiotic susceptibility tests and high-performance liquid chromatography tandem mass spectrometry (HPLC-MS/MS) were employed to screen AMX-degrading bacterial strains in pig manure. The culture conditions were optimized for AMX-degrading bacterial strains using Plackeet–Burman design (PBD), the steepest ascent design, and the response surface methods, coupled with the Box–Behnken design (BBD). The effects of culture time, temperature, rotator (mixing) speed, inoculum level, and initial pH value on the growth of AMX-degrading strains were investigated. Experimental data obtained from BBD were utilized to generate a second-order polynomial regression model for evaluating the effects of the tested variables on the optical density at 600 nm (OD600) of culture solutions as the growth indicator for the screened AMX-degrading strains. (3) Results: The initial pH, culture time, and the inoculum level had significant effects on the OD600 value (growth) of the screened AMX-degrading strains. The initial pH value was found to be the most critical factor influencing the growth of bacteria. The optimized culture condition for the bacterial growth determined by the response surface methodology was: the initial pH of 6.9, culture time of 52 h, and inoculum level of 2%. The average OD value of 12 different fermentation conditions in the initial fermentation tests in this study was 1.72 and the optimization resulted in an OD value of 3.00. The verification experiment resulted in an OD value of 2.94, which confirmed the adequacy of the optimization model for the determining the optimal culture condition. (4) Conclusions: The growth of the screened strain of AMX-degrading bacteria could be optimized by changing the fermentation conditions. The optimization could be achieved by using the Box–Behnken response surface method and Plackett–Burman experimental design.