Nodir Sh. Berdiev, Jamolitdin F. Ziyavitdinov, Akmal M. Asrorov, Shukhratjon S. Olimjonov and Shavkat I. Salikhov
Lipases cleaving oils into fatty acids and glycerol are of great interest for the use in increasing the efficiency of fuels. In this work, a novel lipase from Pseudomonas aeruginosa, P. aeruginosa A12, was isolated by ion-exchange and hydrophobic chromatography. The purity of lipase was shown by electrophoresis and its molecular weight was estimated to be ~ 31.6 kDa. The whole amino acid sequence was analyzed by an LC-MS/MS method. Temperature- and pH-dependent optimum of the enzyme compiled 30 °C and 7.5, respectively. The obtained enzyme exhibited 79 % similarity of amino acid sequence to a lipase isolated from the same strain of P. aeruginosa. Thus, the novel lipase was determined to belong to I.1 subfamily of bacterial true lipases. Three dimensional structure of the isolated lipase isoform was modeled based on obtained sequences. Amino acids forming the catalytic domain were shown in the model. Lid domain is suggested to be in the open conformation. These results provide a potential alternative for enzymatic digestion of fuel oils and serve for the development of fundamental knowledge of lipase activity.
Soyibjon S. Bozorov, Nodir Sh. Berdiev, Uchkun J. Ishimov, Shukhratjon S. Olimjonov, Jamolitdin F. Ziyavitdinov, Akmal M. Asrorov and Shavkat I. Salikhov
The work is devoted to study of seed oil composition of amaranth varieties: Kharkov, Lera, Andijan and Helios, acclimatized in Uzbekistan. We demonstrated the possibility of using reversed-phase HPLC using a refractometric detector, which allows simultaneous determination of squalene and triacylglycerides in plant seeds and determining the authenticity of amaranth oils. Established seed oiliness ranged from 6.39 to 7.81 % of the initial mass. Amaranth oil samples contained quite large amount of unsaturated fatty acids 72.72 – 73.28 %, 1.17 % of which is omega-3-alpha-linolenic acid. The squalene content in the seeds ranged from 0.35 % to 0.55 %. It was established that the squalene content in oils obtained by extraction is greater than the one obtained by cold pressing. In the triacylglyceride composition of the investigated cold-pressed and extracted oils, no significant differences were found.