An Organic Solvent-Tolerant Lipase with Both Hydrolytic and Synthetic Activities from the Oleaginous Fungus Mortierella echinosphaera

Abstract

Lipase enzymes of the oleaginous fungal group Mortierella are rarely studied. However, considering that most commercial lipases are derived from filamentous fungal sources, their investigation can contribute to the cost-effective development of new biotechnological processes. Here, an extracellular lipase with a molecular mass of 30 kDa was isolated from Mortierella echinosphaera CBS 575.75 and characterized. The purified lipase exhibited an optimal p-nitrophenyl palmitate (pNPP)-hydrolyzing activity at 25 °C and pH 6.6–7.0 and proved to be highly stable at temperatures up to 40 °C and under broad pH conditions. The enzyme was active under low temperatures, retaining 32.5% of its activity at 10 °C, and was significantly stable in polar and non-polar organic solvents. The Km, Vmax, and kcat for pNPP were 0.336 mM, 30.4 μM/min, and 45.7 1/min for pNPP and 0.333 mM, 36.9 μM/min, and 55.6 1/min for pNP-decanoate, respectively. The pNPP hydrolysis was inhibited by Hg2+, N-bromosuccinimide, and sodium dodecyl sulfate, while ethylenediaminetetraacetic acid and metal ions, such as Ca2+, Mg2+, Na+, and K+ enhanced the activity. The purified lipase had non-regioselective activity and wide substrate specificity, showing a clear preference for medium-chained p-nitrophenyl esters. Besides its good transesterification activity, the enzyme appeared as a suitable biocatalyst to operate selective esterification reactions to long-chained alkyl esters. Adsorption to Accurel MP1000 improved the storage stability of the enzyme at 5 °C. The immobilized lipase displayed tolerance to a non-aqueous environment and was reusable for up to five cycles without significant loss in its synthetic and hydrolytic activities. These findings confirm the applicability of both the free and the immobilized enzyme preparations in future research.

β-Galactosidase-Producing Isolates in Mucoromycota: Screening, Enzyme Production, and Applications for Functional Oligosaccharide Synthesis

“…There were five R. microsporus strains with notable activity in the Rhizopus group, and one isolate of M. echinosphaera and M. globulifera with promising β-galactosidase production were identified among Mortierella . It is worth mentioning that the same M. echinosphaera was found to be an excellent producer of a lipase with transesterification activity in our previous research [ 25 ]. The combined application of β-galactosidases and lipases can result in sugar–lactate copolymer biomaterials under appropriate conditions [ 26 ] and the possibility to utilize the two biocatalysts from a same organism is a particularly ecofriendly way.…”

Valorization of lipid-rich wastewaters: A theoretical analysis to tackle the competition between polyhydroxyalkanoate and triacylglyceride-storing populations

“…Geotrichum (OtuF0003) has been reported to be cultivated on hydrophobic substrates being capable of secreting extracellular lipases (Hlavsová et al, 2009) and assimilating carbon sources such as fats and oils to use them for growth and storage (Papanikolaou et al, 2017;. The same occurs with Mortierella (OtuF0004), also reported being able to secrete lipases (Jermsuntiea et al, 2011;Kotogán et al, 2018) and produce lipids from hydrophobic substrates such as triolein or sesame oil (Papanikolaou and Aggelis, 2019). However, Apiotrichum (OtuF001) has been only identified as capable of growing and storing lipids on hydrophilic substrates (Papanikolaou and Aggelis, 2011a;Park et al, 1990;Qian et al, 2021;Ykema et al, 1989) and it has not been reported as a lipase producer.…”

Regulation of the Leucine Metabolism in Mortierella alpina

“…BatA required buffer systems with alkaline pH values (pH 8.0), which is a typicial feature for enzymes of the mitochondrial matrix [32] (Figure S4). Its temperature optimum of 25 • C is characteristic for enzymes from cryophilic fungi such as Mortierellaceae [33]. The enzyme converted all BCAAs (L-Ile, L-Leu, L-Val) and their respective α-keto acids in a PLP-dependent manner (Figure 5A-G and Figure S5).…”