Optimization of cholesterol oxidase production and 16S rRNA partial sequence of Bacillus cereus strain KAVK4 isolated from butter

2020

BMC Microbiol

Background: Cholesterol oxidase biosensors have been used to determine the level of cholesterol in different serum and food samples. Due to a wide range of industrial and clinical applications of microbial cholesterol oxidase, isolation and identification of a new microbial source (s) of cholesterol oxidase are very important. Results: The local isolate Streptomyces sp. strain NEAE-94 is a promising source of cholesterol oxidase. It was identified based on cultural, morphological and physiological characteristics; in addition to the 16S rRNA sequence. The sequencing product had been deposited in the GenBank database under the accession number KC354803. Cholesterol oxidase production by Streptomyces anulatus strain NEAE-94 in shake flasks was optimized using surface response methodology. The different process parameters were first screened using a Plackett-Burman design and the parameters with significant effects on the production of cholesterol oxidase were identified. Out of the 15 factors screened, agitation speed, cholesterol and yeast extract concentrations had the most significant positive effects on the production of cholesterol oxidase. The optimal levels of these variables and the effects of their mutual interactions on cholesterol oxidase production were determined using Box-Behnken design. Cholesterol oxidase production by Streptomyces anulatus strain NEAE-94 was 11.03, 27.31 U/mL after Plackett-Burman Design and Box-Behnken design; respectively, with a fold of increase of 6.06 times compared to the production before applying the Plackett-Burman design (4.51 U/mL). Conclusions: Maximum cholesterol oxidase activity was obtained at the following fermentation conditions: g/L (cholesterol 4, yeast extract 5, NaCl 0.5, K 2 HPO 4 1, FeSO 4 .7H 2 O 0.01, MgSO 4 .7H 2 O 0.5), pH 7, inoculum size 4% (v/v), temperature 37°C, agitation speed of 150 rpm, medium volume 50 mL and incubation time 5 days.

“…(1.483 U/mL) [28], Streptomyces lavendulae (2.21 U/mL) [29], Streptomyces sp. (6.2 U/mL) [30], Bacillus cereus (1.67 U/mL) [31] and Streptomyces fradiae (0•03 U/mL) [32].…”

Section: Optimization Of the Selected Significant Variables By Box-bementioning

confidence: 99%

Section: Optimization Of the Selected Significant Variables By Box-bementioning

confidence: 99%

Identification of cholesterol-assimilating actinomycetes strain and application of statistical modeling approaches for improvement of cholesterol oxidase production by Streptomyces anulatus strain NEAE-94

2020

BMC Microbiol

“…In the current study, the maximum enzyme activity (yield) of cholesterol oxidase of Streptomyces aegyptia NEAE-102 was 15.631 UmL −1 , which was higher than the activity of cholesterol oxidase enzyme of Streptomyces lavendulae (2 UmL − 1 ) 36 , Rhodococcus equi no. 23 (0·24 UmL −1 ) 37 , Streptomyces fradiae (0·03 UmL −1 ) 38 , Bacillus cereus (1.67 UmL −1 ) 39 , Streptomyces sp. (6.2 UmL −1 ) 35 , Brevibacterium sp.…”

Section: Resultsmentioning

confidence: 99%

Extracellular cholesterol oxidase production by Streptomyces aegyptia, in vitro anticancer activities against rhabdomyosarcoma, breast cancer cell-lines and in vivo apoptosis

Soliman

2018

Sci Rep

In recent years, microbial cholesterol oxidases have gained great attention due to its widespread use in medical applications for serum cholesterol determination. Streptomyces aegyptia strain NEAE-102 exhibited high level of extracellular cholesterol oxidase production using a minimum medium containing cholesterol as the sole source of carbon. Fifteen variables were screened using Plackett–Burman design for the enhanced cholesterol oxidase production. The most significant variables affecting enzyme production were further optimized by using the face-centered central composite design. The statistical optimization resulted in an overall 4.97-fold increase (15.631 UmL−1) in cholesterol oxidase production in the optimized medium as compared with the unoptimized medium before applying Plackett Burman design (3.1 UmL−1). The purified cholesterol oxidase was evaluated for its in vitro anticancer activities against five human cancer cell lines. The selectivity index values on rhabdomyosarcoma and breast cancer cell lines were 3.26 and 2.56; respectively. The in vivo anticancer activity of cholesterol oxidase was evaluated against Ehrlich solid tumor model. Compared with control mice, tumors growth was significantly inhibited in the mice injected with cholesterol oxidase alone, doxorubicin alone and cholesterol oxidase/doxorubicin combination by 60.97%, 72.99% and 97.04%; respectively. These results demonstrated that cholesterol oxidase can be used as a promising natural anticancer drug.

“…In the current study, fifteen experiments with various combinations of agitation speed, cholesterol concentration and yeast extract concentration were performed and the experimental and predicted cholesterol oxidase production and residuals for the fifteen trials are provided in Table 5. [53] and Streptomyces fradiae (0•03 U/mL) [21].…”

Section: Burman Designmentioning

confidence: 99%

Identification of cholesterol-assimilating actinomycetes strain and application of statistical modeling approaches for improvement of cholesterol oxidase production by Streptomyces anulatus strain NEAE-94

2019

Preprint

Background Cholesterol oxidase biosensors have been applied to detect cholesterol level in different in serum and foods samples. Due to a wide range of industrial and clinical applications of microbial cholesterol oxidase, isolation and detection of new microbial source (s) of cholesterol oxidase are very important.Results Among the potential strains, Streptomyces sp. strain NEAE-94 was chosen and identified based on cultural, morphological and physiological characteristics; in addition to the 16S rRNA sequence which had been deposited in the GenBank database under the accession number KC354803. Cholesterol oxidase production in shake flask by Streptomyces anulatus strain NEAE-94 was optimized using response surface methodology. The production parameters were first screened using a Plackett-Burman design and the parameters with significant effects on the production of cholesterol oxidase were identified. Out of the fifteen factors screened, agitation speed, cholesterol and yeast extract concentration were selected due to significant positive effects on the production of cholesterol oxidase. The optimal levels of these variables and the effects of their mutual interactions on cholesterol oxidase production were determined using Box-Behnken design. The maximum cholesterol oxidase activity (27.31 U/mL) was achieved at cholesterol concentration (4 g/L), the agitation speed (150 rpm/min) and yeast extract concentration (5 g/L). In comparison with cholesterol oxidase production by Streptomyces anulatus strain NEAE-94 before the application of Plackett-Burman design, the statistical optimization resulted in an increased production by 4.66 times.Conclusions The maximal cholesterol oxidase activity is obtained at the following fermentation conditions: g/L (cholesterol 4, yeast extract 5, NaCl 0.5, K 2 HPO 4 1, FeSO 4 .7H 2 O 0.01, MgSO 4 .7H 2 O 0.5), pH 7, inoculum size 4% (v/v), temperature 37°C, agitation speed 150 rpm/min, medium volume 100 mL and incubation time 5 days.