Enhancement of Candida rugosa lipase production by using different control fed‐batch operational strategies

Abstract

Simulation studies have predicted that maximum lipase activity is reached with fed-batch operation strategies. In this work, two different fed-batch operational strategies have been studied: constant substrate feeding rate and specific growth rate control. A constant substrate feeding rate strategy showed that maximum aqueous lipolytic activity (55 U/mL) was reached at low substrate feeding rates, whereas lipase tends to accumulate inside the cell at higher rates of substrate addition. In the second fed-batch strategy studied, a feedback control strategy has been developed based on the estimation of state variables (X and mu) from the measurement of indirect variables such as CER by means of mass spectrometry techniques. An on-off controller was then used to maintain the specific growth rate at the desired value by adjusting the substrate feeding rate. A constant specific growth rate strategy gave higher final levels of aqueous lipolytic activity (117 U/mL) at low specific growth rates. At higher specific growth rates the enzyme remained accumulated inside the cell, as was observed with a constant feeding fed-batch strategy. With a constant specific growth rate strategy, lipase production by Candida rugosa was enhanced 10-fold compared to a batch operation. Purification studies have demonstrated that lipolytic and esterasic specific activity ratios of Candida rugosa isoenzymes can be modified by using different operational conditions. These studies have also showed that the isoenzymes obtained in a controlled growth rate strategy are around three- to four-fold more active than those obtained in a constant feeding rate strategy.

Thermostable lipolytic enzymes production in batch and continuous cultures of Thermus thermophilus HB27

“…3). These results are in accordance to the report by Gordillo et al [29]. They determined that at several dilution rates the lipolytic enzyme productivity in continuous culture was slightly higher than in batch cultures.…”

“…However, there are no reports dealing with lipolytic enzyme production by T. thermophilus in continuous mode. Therefore, considering that the lipase production seems to be associated with the microorganism growth, a continuous operation mode could improve the yield and productivity obtained in batch cultures [29]. With this aim, experiments in continuous mode were carried out in a stirred tank bioreactor at 650 rpm and hydraulic retention time of 2 days without recycling and under sterile conditions.…”

Optimization and Modeling of Process Parameters for Lipase Production by Bacillus brevis

“…Lipase from B. licheniformis was produced effectively under similar conditions (Khyami-Horani 1996). The speed of agitation in aerobic batch process is an important parameter since it involves in maintaining the level of oxygen in the medium (Gordillo et al 1998). However, the fermentation performed at higher DO level resulted in an increase in growth rate and affected the lipase production (Elibol and Ozer 2000).…”

Recombinant Candida rugosa LIP2 expression in Pichia pastoris under the control of the AOX1 promoter

“…Samples obtained from the diafiltrate showed lipolytic activity, and SDS-PAGE analyses revealed the presence of the monomeric Lip2 form, although dimer form was also observed. Total lipolytic activity detected in the diaultrafiltrate was 2 × 10 6 AU; 4-fold higher than obtained with native C. rugosa fed-batch fermentation at low specific growth rate, the best operational fed-batch strategy tested [41].…”