Effect of Aeration and Agitation Regimes on Lipase Production by Newly Isolated Rhodotorula mucilaginosa–MTCC 8737 in Stirred Tank Reactor Using Molasses as Sole Production Medium

Abstract

The influence of media and process parameters (aeration and agitation) on fermentation broth rheology and biomass formation has been studied in 1.5-l stirred tank reactor for lipase production using Rhodotorula mucilaginosa MTCC 8737. Molasses, as sole production medium, is used for lipase production by varying aeration (1, 2, and 3 vvm) and agitation speeds (100, 200, and 300 rpm). Maximum lipase activity of 72 U/ml was obtained during 96 h of fermentation at 2 vvm, 200 rpm, pH 7, and 25 +/- 2 degrees C temperature. Lipase production kinetics with respect to dry cell weight of biomass showed Y (P/S) of 25.71 U/mg, specific product formation of 10.9 U/mg DC, and Y (X/S) 2.35 mg/mg. Maximum lipase activity (MC 2) of 56 U/ml was observed at 1% molasses, and a further increase in the molasses concentration of (%) 1.5 and 2 inhibited the product formation of lipase with 15 and 8.5 U/ml, respectively. The production kinetics of molasses media showed Y (P/X) was 14 U/mg DC, Y (P/S) 16 U/mg, and Y (X/S) 1.14 mg/mg during 96 h of bioreactor operation. The k(L)a values for all batches (MC 1-MC 4) at 96 h of fermentation were 32, 28, 21, and 19/h, and the |oxygen transfer rate were 54.4, 56, 35.7, and 17.29 mg/l h, respectively. Increase in molasses concentration resulted in decreased lipase activity by increase in viscosity of the fermentation broth.

Evaluation of a novel Bacillus strain from a north‐western Spain hot spring as a source of extracellular thermostable lipase

“…This could be attributed to the occurrence of mechanical and/or oxidative stress in the cultures. In a similar way, Portumarthi et al 36 found that intermediate conditions of aeration and agitation were the most suitable to obtain lipases in stirred tank cultures of Rhodotorula mucilaginosa-MTCC 8737.…”

A Review on Microbial Lipases Production

“…Although lipases from C. rugosa and C. antarctica have been extensively used in different fields, there are several recent publications reporting the production of lipases by other yeasts, as shown in Table 1. Potumarthi et al (2008) collected marine soil samples near an oil extraction platform in the Arabian Sea. After the isolation of the colonies, they were transferred to plates containing 2% tributyrin and incubated at 35°C for 3-4 days.…”

“…When comparing both tested media, the best results were obtained using the one based on peptone, yeast extract, NaCl, and olive oil. Potumarthi et al (2008) employed molasses as sole carbon source for lipase production by R. mucilaginosa MTCC 8737. A maximum lipase activity was verified using 1% of molasses.…”

“…The other environmental factors observed in a partitioned scale-down reactor, i.e., methyl oleate dispersion and pH fluctuations, led to a less severe stress interpreted only by a decrease in microbial yield and hence in the extracellular lipase-specific production rate. Potumarthi et al (2008) studied the influence of media and process parameters (aeration and agitation) on fermentation broth rheology and biomass formation in 1.5-L stirred tank reactor for lipase production using R. mucilaginosa MTCC 8737. A maximum lipase activity of 72 U mL −1 was obtained during 96 h of fermentation at 2 vvm, 200 rpm, pH 7, and 25°C.…”

Multiple Responses Optimization and Modeling of Lipase Production by Rhodotorula mucilaginosa MTCC-8737 Using Response Surface Methodology

“…Response surface methodology (RSM) has been widely used to evaluate and understand the interactions between different process parameters [5]. RSM was applied successfully for optimizing process parameters for various processes in biotechnology [6][7][8][9][10][11][12].…”