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Albany 2019: 20th Conversation - Abstracts

Albany 2019
Conversation 20
June 11-15 2019
Adenine Press (2019)

Zinc Supplementation Stimulates Lipid Production in Torulaspora globose Yeast

The practical importance of microbial lipids causes great interest of researchers to the problem of their synthesis and regulation. The experimental approaches in which the cell growth and the direction of various biosynthetic processes can be controlled are well-known. The limitation of cell growth by nutrition elements is one of the ways to shift metabolism into directional synthesis of lipids (Athenaki et al., 2018).

At present, the ethanol is considered to be a promising carbon source in various biotechnological processes, because it can be produced from sugarcane, beet, corn, lignocellulose and other renewable materials. It does not contain harmful impurities; it is well assimilated by yeast and dissolves in water in any proportions. Several companies in the US and Switzerland have created food products based on microbial biomass produced from ethanol (Weusthuis et al., 2011). It should be noted that the large-scale production of lipids from ethanol is still limited by the lack of basic knowledge about fermentation conditions conducive to product overproduction.

Analysis of the literature data shows the exceptional role of zinc in the regulation of cell metabolism and physiology. Besides acting as a cofactor for many enzymes (dehydrogenases, aldolases, polymerases, and proteases) (Dedyukhina, Eroshin 1991; Tomaszewska et al., 2014; Kamzolova et al., 2018) zinc is also required for the structural stability of zinc finger proteins, many of which exert important controls on cellular metabolic processes (Hamed, Arya, 2016).

The purpose of this work was to study the effect of various zinc concentrations on growth and lipid synthesis of yeast Torulaspora globosa VKPMY-953 using a chemostate regimen (D=0.05 h-1). As seen from Table, the limitation of the growth of T. globosa by zinc (0.001 mg/L) sharply reduced the biomass yield (YX/S) (in 2.7 times), lipid content (in 3 times) and lipid yield (in 3.6 times) as compare to high Zn concentration (2.8 mg/L). At the same time, the protein content was maximum (37.96% from dry biomass) under condition of Zn deficiency.

As seen from Table, the lipids contained С14–С18 acids with a prevalence of palmitic (C16:0), palmitoleic (C16:1) and oleic (C18:1) acids.

In this study, we focused on the palmitoleic acid (C16:1), which is considered as a novel lipokine (Athenaki et al., 2018). As seen from Table, a large amount of palmitoleic acid (37.5 – 41.7% of lipids) was synthesized at zinc concentration in the range from 0.1 to 2.8 mg/L.

The activity of ∆-9 desaturase involved in the conversion of palmitic into palmitoleic acid was evaluated by measuring the ratio С16:1/С16. In our experiments, the ratio С16:1/С16 completely correlated with a change in the palmitoleic acid content of lipids (Table).

table-kamz.png

The reported research was funded by RFBR (project № 18-38-00794_mol_а).

References

    Athenaki, M., Gardeli, C., Diamantopoulou, P., Tchakouteu, S.S., Sarris, D., Philippoussis, A., Papanikolaou, S. (2018) Lipids from yeasts and fungi: physiology, production and analytical considerations. J. Appl. Microbiol. 124(2), 336-367. doi: 10.1111/jam.13633.

    Dedyukhina E.G., Eroshin V.K. (1991) Essential metal ions in the control of microbial metabolism. Process Biochem. 26(1), 31-37. 10.1139/cjm-2018-0050

    Hamed, M.Y., Arya, G. (2016) J. Biomol. Struct. Dyn. 34(5), 919-34. doi: 10.1080/07391102.2015.1068224.

    Kamzolova, S.V., Shamin, R.V., Stepanova, N.N., Morgunov, G.I., Lunina, J.N., Allayarov, R.K., Samoilenko, V.A., Morgunov, I.G. (2018) Fermentation conditions and media optimization for isocitric acid production from ethanol by Yarrowia lipolytica. Biomed. Res. Int. 2543210. doi: 10.1155/2018/2543210

    Tomaszewska, L., Rymowicz, W., Rywińska, A. (2014) Mineral supplementation increases erythrose reductase activity in erythritol biosynthesis from glycerol by Yarrowia lipolytica. Appl. Biochem. Biotechnol. 172(6), 3069-3078. doi: 10.1007/s12010-014-0745-1.

    Zhao, X.Q., Bai, F.W. (2012) Zinc and yeast stress tolerance: micronutrient plays a big role. J. Biotechnol. 158(4), 176-183. doi: 10.1016/j.jbiotec.2011.06.038.

    Weusthuis, R., Aarts, J., Sanders, J. (2011) From biofuel to bioproduct: is bioethanol a suitable fermentation feedstock for synthesis of bulk chemicals? Biofuels Bioprod. Bioref., 5, 486-494.

Svetlana V. Kamzolova1
Nadezda N. Stepanova1
Grigorii I. Morgunov 2
Ramil K. Allayarov1
and Igor G. Morgunov1

1 Federal Research Center Pushchino Center for Biological Research of the Russian Academy of Sciences
G.K. Skryabin Institute of Biochemistry and Physiology of Microorganisms, RAS
Pushchino, Moscow region 142290, Russia

2 Peoples' Friendship University of Russia (RUDN University)
Miklukho-Maklaya str. 6
Moscow, P.O. Box 117198, Russia

Ph: (007) 9264145620
Fx: (007) 495-9563370
Email: kamzolova@rambler.ru