Enhanced rhamnolipid production by <i>Pseudomonas aeruginosa </i>
USM-AR2 via fed-batch cultivation based on maximum substrate uptake rate

Noh, Nur Asshifa Md; Salleh, Salwa Mohd; Yahya, Ahmad Shukri

doi:10.1111/lam.12236

Cited by 21 publications

(7 citation statements)

References 21 publications

(48 reference statements)

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“…Optimum fermentation conditions were found to be an inoculum size of 1%v/v, a temperature of 30 °C and a pH of 8. These results suggest that SSF may possibly be a feasible substitute for SLF to produce RLs since our maximum yield was comparable with values that have been obtained in SLF: 23.6 g/l (Noh et al 2014), 32 g/l (Matsufuji et al 1997), 36.7 g/l (Muller et al 2011), and 46 g/l (Linhardt et al 1989). These findings imply that RL production by P. aeruginosa 15GR in static tray bioreactors may be successful (Durand 2003).…”

Section: Discussionsupporting

confidence: 85%

“…Rhamnolipids (RLs) are promising biosurfactants mainly used for environmental applications because of their impressive emulsifying and surface active properties. However, their use is limited because of their elevated costs relative to that of chemical surfactants (Noh et al 2014). Research on RLs production was mainly directed to submerged liquid fermentation (SLF) until recently.…”

Section: Introductionmentioning

confidence: 99%

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Rhamnolipid production by a gamma ray-induced Pseudomonas aeruginosa mutant under solid state fermentation

El-Housseiny¹,

Aboshanab

Aboulwafa

et al. 2019

AMB Expr

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Solid-state fermentation has a special advantage of preventing the foaming problem that obstructs submerged fermentation processes for rhamnolipid production. In the present work, a 50:50 mixture of sugarcane bagasse and sunflower seed meal was selected as the optimum substrate for rhamnolipid production using a Pseudomonas aeruginosa mutant 15GR and an impregnating solution including 5% v/v glycerol. Using Box–Behnken design, the optimum fermentation conditions were found to be an inoculum size 1% v/v, temperature 30 °C and unlike other studies, pH 8. These optimized conditions yielded a 67% enhancement of rhamnolipid levels reaching 46.85 g rhamnolipids per liter of impregnating solution, after 10 days, which was about 5.5 folds higher than that obtained by submerged liquid fermentation. Although maximum rhamnolipids concentration was obtained after 10 days of incubation, rhamnolipids concentration already reached high levels (41.87 g/l) after only 6 days. This rhamnolipid level was obtained in a shorter time and using lower carbon source concentrations than most studies reported so far. The findings obtained indicate an enormous potential for employing solid-state fermentation for rhamnolipid production by the studied isolate.

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Section: Discussionsupporting

confidence: 85%

Section: Introductionmentioning

confidence: 99%

Rhamnolipid production by a gamma ray-induced Pseudomonas aeruginosa mutant under solid state fermentation

El-Housseiny¹,

Aboshanab

Aboulwafa

et al. 2019

AMB Expr

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“…For instance, the use of water-insoluble carbon sources such as palm oil and diesel generally produce rhamnolipids in higher titers as compared to water-soluble carbon sources (e.g. glucose) [ 29 , 66 ]. The feeding profile of substrates, especially the carbon source, is also an important parameter as fed-batch cultivation is found to be the more effective than batch cultivation to obtain high rhamnolipid titers [ 57 , 65 – 67 ].…”

Section: Application Of Various Strategies To Increase Rhamnolipid Yimentioning

confidence: 99%

Microbial production of rhamnolipids: opportunities, challenges and strategies

2017

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Rhamnolipids are a class of biosurfactants which contain rhamnose as the sugar moiety linked to β-hydroxylated fatty acid chains. Rhamnolipids can be widely applied in many industries including petroleum, food, agriculture and bioremediation etc. Pseudomonas aeruginosa is still the most competent producer of rhamnolipids, but its pathogenicity may cause safety and health concerns during large-scale production and applications. Therefore, extensive studies have been carried out to explore safe and economical methods to produce rhamnolipids. Various metabolic engineering efforts have also been applied to either P. aeruginosa for improving its rhamnolipid production and diminishing its pathogenicity, or to other non-pathogenic strains by introducing the key genes for safe production of rhamnolipids. The three key enzymes for rhamnolipid biosynthesis, RhlA, RhlB and RhlC, are found almost exclusively in Pseudomonas sp. and Burkholderia sp., but have been successfully expressed in several non-pathogenic host bacteria to produce rhamnolipids in large scales. The composition of mono- and di-rhamnolipids can also be modified through altering the expression levels of RhlB and RhlC. In addition, cell-free rhamnolipid synthesis by using the key enzymes and precursors from non-pathogenic sources is thought to not only eliminate pathogenic effects and simplify the downstream purification processes, but also to circumvent the complexity of quorum sensing system that regulates rhamnolipid biosynthesis. The pathogenicity of P. aeruginosa can also be reduced or eliminated through in vivo or in vitro enzymatic degradation of the toxins such as pyocyanin during rhamnolipid production. The rhamnolipid production cost can also be significantly reduced if rhamnolipid purification step can be bypassed, such as utilizing the fermentation broth or the rhamnolipid-producing strains directly in the industrial applications of rhamnolipids.

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“…Pseudomonas aeruginosa USM-AR2, a hydrocarbon-utilizing bacterium, has been shown to secrete copious amounts of rhamnolipid when grown on waterimmiscible substrates (Md Noh et al, 2014;Noh et al, 2012). Rhamnolipid has been explored as a potential antifungal agent for environmental-friendly agricultural practice.…”

Section: Introductionmentioning

confidence: 99%

The Potential of Rhamnolipid as Biofungicide against Rigidoporus microporus Isolated from Rubber Tree (Hevea brasiliensis)

Hadi¹,

Nasir²,

Noh³

et al. 2022

JTAS

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Rigidoporus microporus is the main causal of white root disease (WRD) in rubber trees (Hevea brasiliensis). The present study investigates the use of rhamnolipid, a biosurfactant produced by Pseudomonas aeruginosa USM-AR2 against R. microporus. In vitro dose-responses towards rhamnolipid were determined on different isolates of R. microporus using the poisoned food technique (PFT). Inhibition of mycelial growth was found to be dose-dependent, with the highest inhibition of 76.74% at 200 ppm (pH 6.29) on SEG isolate. On the contrary, the lowest concentration of rhamnolipid applied at 10 ppm (pH 5.97) had effectively inhibited the growth of RL 19 to 34.36%. AM isolate was assumed to be the most aggressive pathogen due to the lowest inhibition recorded on all rhamnolipid concentrations tested. At the same time, RL 19 was the least aggressive pathogen compared to the other R. microporus isolates. The rhamnolipid concentrations (ppm), which reduced mycelial growth at 50% (EC50), were recorded at 17.82 ppm for AM isolate, 12.52 ppm for RL 26, and 11.80 ppm for RL 19 isolate. This result indicated that rhamnolipid concentrations to inhibit 50% of mycelial growth might vary based on the aggressiveness and the virulence levels of different R. microporus isolates. It was found that pH changes after incorporating rhamnolipid into the PDA were not the main factor affecting the inhibition of R. microporus isolates. It is obvious that rhamnolipid had an inhibitory effect on fungal growth in vitro. It is the first report on rhamnolipid that has been shown to control R. microporus potentially.

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Enhanced rhamnolipid production by Pseudomonas aeruginosa USM-AR2 via fed-batch cultivation based on maximum substrate uptake rate

Cited by 21 publications

References 21 publications

Rhamnolipid production by a gamma ray-induced Pseudomonas aeruginosa mutant under solid state fermentation

Rhamnolipid production by a gamma ray-induced Pseudomonas aeruginosa mutant under solid state fermentation

Microbial production of rhamnolipids: opportunities, challenges and strategies

The Potential of Rhamnolipid as Biofungicide against Rigidoporus microporus Isolated from Rubber Tree (Hevea brasiliensis)

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