Isolation and Characterization of Bacillus megaterium IBBPo17 a Solvent-Tolerant Bacterium

Stancu, Mihaela Marilena

doi:10.1007/s12649-018-0354-2

Cited by 7 publications

(9 citation statements)

References 38 publications

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“…This Gram-positive bacterium, which possesses alkB1 and ndoM catabolic genes, was able to survive and grow in the presence of short-chain n -alkanes, such as n -decane, n -hexane, and cyclic solvents, such as cyclohexane, ethylbenzene, styrene, and toluene. As previously observed, B. megaterium IBB Po17 produced extracellular enzymes (protease, amylase, cellulase) and extracellular surfactant when the growth was done on nutrient-rich LB medium [ 13 ]. In the present study, we further investigated the ability of B. megaterium IBB Po17 to produce biosurfactant when the growth was done in the presence of 5% n -hexadecane on basal medium supplemented with different nitrogen (i.e., yeast extract, proteose peptone) or carbon (i.e., starch, cellulose) sources.…”

Section: Discussionmentioning

confidence: 63%

“…SEM studies of B. megaterium IBB Po17 grown in the presence of 5% n -hexadecane on medium supplemented with yeast extract, proteose peptone, starch, or cellulose revealed changes in cell morphology. As observed, B. megaterium IBB Po17 grown on LB medium ranges between 1.6 and 3.8 µm in length [ 13 ]. The cell length of B. megaterium IBB Po17 grown in the presence of n -hexadecane on medium supplemented with yeast extract, proteose peptone, starch, or cellulose ranges between 0.8 and 5.5 µm ( Figure 1a–d ).…”

Section: Resultsmentioning

confidence: 95%

“…B. megaterium strain IBB Po17 (GenBank KX499518) was formerly isolated from an oily sludge sample by crude oil enrichment [ 13 ]. This Gram-positive bacterium, which possesses alkB1 and ndoM catabolic genes, was able to survive and grow in the presence of short-chain n -alkanes, such as n -decane, n -hexane, and cyclic solvents, such as cyclohexane, ethylbenzene, styrene, and toluene.…”

Section: Discussionmentioning

confidence: 99%

“…Extracellular and whole-cell proteins were extracted from the cell-free culture broths and cell pellets, respectively, as previously described by Stancu [ 13 ]. Extracted proteins were dissolved in Laemmli buffer and denatured at 96°C for 10 min.…”

Section: Methodsmentioning

confidence: 99%

“…Biosurfactant was extracted from the cell-free culture broths with chloroform–methanol (2:1, v/v), as previously described by Stancu [ 13 ]. Thin-layer chromatography (TLC) analyses were carried out using a CAMAG TLC system (Muttenz, Switzerland).…”

Section: Methodsmentioning

confidence: 99%

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Biosurfactant production by a Bacillus megaterium strain

Stancu

2020

Open Life Sciences

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The aim of the present study was to investigate the ability of Bacillus megaterium IBBPo17 (GenBank KX499518) cells to produce biosurfactant when the growth was done in the presence of long-chain n-alkane n-hexadecane on medium supplemented with yeast extract, proteose peptone, starch, or cellulose. B. megaterium IBBPo17 revealed a higher growth in the presence of n-hexadecane when the medium was supplemented with yeast extract, proteose peptone, or starch, compared with cellulose. Biosurfactant production was higher when B. megaterium IBBPo17 was grown in the presence of n-hexadecane on yeast extract, proteose peptone, or starch supplemented medium, compared with biosurfactant produced on cellulose supplemented medium. A direct correlation between cell growth and biosurfactant production was observed. When the growth of B. megaterium IBBPo17 cells was higher, the decrease in pH values of the medium was higher too, and more amount of CO2 was released. Changes in cell morphology, aggregation of the cells in clusters, and biofilm formation were observed when B. megaterium IBBPo17 was grown in the presence of n-hexadecane on medium supplemented with yeast extract, proteose peptone, starch, or cellulose. Due to its physiological abilities, this Gram-positive bacterium could be a promising candidate for the bioremediation of petroleum hydrocarbon polluted environments.

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Section: Discussionmentioning

confidence: 63%

Section: Resultsmentioning

confidence: 95%

Section: Discussionmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

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Biosurfactant production by a Bacillus megaterium strain

Stancu

2020

Open Life Sciences

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Cytochrome P450-mediated N-demethylation of noscapine by whole-cell biotransformation: process limitations and strategies for optimisation

Richards

Jarrold²,

Bowser³

et al. 2020

Journal of Industrial Microbiology and Biotechnology

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Cytochrome P450 enzymes catalyse reactions of significant industrial interest but are underutilised in large-scale bioprocesses due to enzyme stability, cofactor requirements and the poor aqueous solubility and microbial toxicity of typical substrates and products. In this work, we investigate the potential for preparative-scale N-demethylation of the opium poppy alkaloid noscapine by a P450BM3 (CYP102A1) mutant enzyme in a whole-cell biotransformation system. We identify and address several common limitations of whole-cell P450 biotransformations using this model N-demethylation process. Mass transfer into Escherichia coli cells was found to be a major limitation of biotransformation rate and an alternative Gram-positive expression host Bacillus megaterium provided a 25-fold improvement in specific initial rate. Two methods were investigated to address poor substrate solubility. First, a biphasic biotransformation system was developed by systematic selection of potentially biocompatible solvents and in silico solubility modelling using Hansen solubility parameters. The best-performing biphasic system gave a 2.3-fold improvement in final product titre compared to a single-phase system but had slower initial rates of biotransformation due to low substrate concentration in the aqueous phase. The second strategy aimed to improve aqueous substrate solubility using cyclodextrin and hydrophilic polymers. This approach provided a fivefold improvement in initial biotransformation rate and allowed a sixfold increase in final product concentration. Enzyme stability and cell viability were identified as the next parameters requiring optimisation to improve productivity. The approaches used are also applicable to the development of other pharmaceutical P450-mediated biotransformations.

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