Thermostable lipase from a newly isolated Staphylococcus xylosus strain; process optimization and characterization using RSM and ANN

Abstract

Normal feed forward back-propagation artificial neural network (ANN) and cubic backward elimination response surface methodology (RSM) were used to build a predictive model of the combined effects and optimization of culture parameters for the lipase production of a newly isolated Staphylococcus xylosus. The results demonstrated a high predictive accuracy of artificial neural network compared to response surface methodology. The optimum operating condition obtained from the ANN model was found to be at 30ºC incubation temperature, pH 7.5, 60 hrs incubation period, 1.8% inoculum size and 60 rpm agitation. The lipase production increased 3.5 fold for optimal medium. The produced enzyme was characterized biochemically and this is the first report about a mesophilic staphylococci bacterium with a high thermostable lipase which is able to retain 50% of its activity at 70ºC after 90 min and at 60ºC after 120 min. This lipase is also acidic and alkaline resistant which remains active after 24 hrs in a broad range of pH (4-11).

Improvement of Medium Chain Fatty Acid Content and Antimicrobial Activity of Coconut Oil via Solid-State Fermentation Using a MalaysianGeotrichum candidum

“…Likewise, higher moisture levels than optimum value cause decreased porosity, lower oxygen transfer, and alteration in solid-state particle structure [29]. In our previous study, RSM revealed good understanding in complicated biological systems [31]. A reduced cubic-fitted model (Table 2) revealed its potential to determine the best operative conditions for G. candidum local strain lipolytic activity towards coconut oil hydrolysis and MCFA production.…”

Cloning and characterization of newly isolated lipase from Enterobacter sp. Bn12

“…In comparison with the other thermostable bacterial lipases (Kim et al , 1996; Meilleur et al , 2009; Sarkar et al , 2012), ELB12 had notable specific activity. Unlike many of them (Khoramnia et al , 2010, 2011; Sarkar et al , 2012), the lipase showed less thermostability at high temperatures. Nevertheless, the specific activity of ELBn12 even after 1 h incubation at 70 °C (1000 U/mg) was remarkable and more than original activity of the many reported thermostable bacterial lipases (Khoramnia et al , 2011; Meilleur et al , 2009; Sarkar et al , 2012).…”

“…Some examples of these include thermostable lipases from Bacillus subtilis EH 37 (Ahmed et al , 2010), citrobacter freundii (Guanasekaran et al , 2006), Staphylococcus xylosus (Khoramnia et al , 2010), Acinetobacter sp. (Khoramnia et al , 2011), and Proteus vulgaris K80 (Kim et al , 1996).…”

“…Although there are some characterized alkaline thermostable lipases from different microorganisms or metagenomic libraries (Ahmed et al , 2010; Guanasekaran et al , 2006; Khoramnia et al , 2010; Kim et al , 1996; Nawani et al , 1998; Sarkar et al , 2012), a few of them are stable in the presence of organic solvents (Ahmed et al , 2010; Guanasekaran et al , 2006; Nawani et al , 1998). In this study, we report functional screening, sequencing and characterization of a novel organic solvent- and thermo-stable alkaline lipase from a mesophilic Enterobacter species.…”

An Expository Paper on Optimal Design

“…Khoramnia et al (2010) published an article in the Electronic Journal of Biotechnology describing a process characterization and optimization case study. The investigators were interested in maximizing the lipase activity of a bacterial culture.…”