A process for extracellular thermostable lipase production by a novel Bacillus thermoamylovorans strain

Abstract

A lipolytic enzyme-producing thermophilic microorganism, recently isolated from a hot spring in Galicia (North Western Spain), has been investigated. First, the strain was genetically identified and tentatively named Bacillus thermoamylovorans CH6B. It produced significant levels (around 450 U/L) of extracellular lipolytic activity in shake flask cultures, and the most suitable conditions for this biological process were found at temperatures between 50 and 55 °C, and an initial pH value around 7.0. Next, a preliminary scaling up of the process was carried out in a 5-L stirred tank bioreactor, and it was concluded that operation at agitation and aeration rates of 300 rpm and 0.33 vvm, respectively, were advisable. In both type of cultures, the results were successfully fitted to logistic equations, and the relationship between lipase production and cell growth was investigated. Furthermore, some relevant properties of the crude lipolytic enzyme extracts were assessed. The crude biocatalyst preferentially hydrolysed p-nitrophenyl esters of medium and long-chain fatty acids. Thermal stability in aqueous solution of the produced enzyme was also promising, and the deactivation profiles were fitted to a series-type deactivation model.

Isolation and characterization of a thermostable lipase from <i>Bacillus thermoamylovorans</i> NB501

“…As shown in Table 1, the enzyme was active with a wide range of substrates and showed a remarkably higher activity with pNP-myristate (C14), followed by pNP-palmitate (C16), which constitutes approximately 11% of soybean oil (Hammond et al, 2005). The activity profile was similar to that of a thermophilic lipase from B. thermoamylovorans CH6B (Deive et al, 2012). However, Lip501r showed a higher relative activity for pNP-butyrate (75% to pNPmyristate, Table 1) compared to CH6B lipase (less than 10%).…”

“…The optimal pH and apparent optimal temperature of the enzymes were 8 and 60∞C, respectively. In a previous report of an extracellular lipase from B. thermoamylovorans CH6B, the optimal pH and temperature were 7 and 50-55∞C, respectively (Deive et al, 2012). However, cloning of this lipase gene has not been reported until now.…”

Statistical enhancement of lipase extracellular production byBacillus stratosphericusPSP8 in a batch submerged fermentation process

“…However, the obtained maximum specific lipase production and growth rates were lower than those reported by Deive et al . () who recorded 0·345 and 0·895 h −1 for Bacillus thermoamylovorans CH6B respectively. This might be attributed to the different hydrodynamic conditions of cultivation, caused by aeration and agitation.…”

Efficient biosynthesis of a chitinase from Halobacterium salinarum expressed in Escherichia coli

“…The search for more efficient bioprocesses at an industrial scale has prompted the investigation of a number of small‐scale bioreactor systems, which tended to focus on stirred tank or airlift designs because of their geometrical similarity with the large‐scale bioreactors most likely to be used for industrial manufacture . Besides, these configurations allow evaluating the importance of different decisive engineering variables such as agitation and aeration on the production of chitinolytic enzymes.…”