Using inorganic elements to control cell growth and lipid accumulation in Lipomyces starkeyi.

Abstract

We studied how to control the ability of Lipomyces starkeyi cells to grow and accumulate lipid by adding inorganic elements. Adding Zn2 +, Mn2 +, and monopotassium phosphate at a stationary phase of growth caused rapid changes. However, adding these elements individually did not induce any marked changes in the cell growth and lipid accumulation. When these elements were added simultaneously, the yeast underwent a second logarithmic growth and the respiration rate increased. Concurrently, this addition stopped the normal increase in the amount of lipid in the culture (mg of lipid ml of culture), and decreased the lipid content of the cells (mg of lipid/108 cells). The periods of second logarithmic growth and the cessation of lipid accumulation were shortened when monopotassium phosphate was not added. The function of monopotassium phosphate was replaced by another buffer chemical.Artificial modification of the physiological conditions of growing microorganisms has often been used as a way to control metabolite production. In Lipomyces starkeyi grown in batch cultures, cell growth and lipid accumulation gradually change with the progress of the growth phases (1, 2). If the progress of the growth phases can be artificially controlled, cells with different abilities can be easily obtained. Development of such a control method enables us to study the metabolism of lipid accumulation in the yeast.In our earlier report, we showed that the concentration of certain inorganic micro-ions seriously affect the cell growth and the lipid accumulation (3). That raised the possibility that these changes, which accompany the progress of growth phases, could be controlled artificially by changing the concentration of inorganic elements midway in the culture. In the present study, this possibility was examined.

Assessing an effective feeding strategy to optimize crude glycerol utilization as sustainable carbon source for lipid accumulation in oleaginous yeasts

“…L. starkeyi (Fig. 4 c) produced one or two large lipid bodies in their spherical cells (as shown in [ 31 ]). The small lipid bodies (less than 1 μm diameter), which were already visible in the cells at the beginning of the feeding phase (28 h), increased in size to more than 6 μm diameter after 144 h of cultivation.…”

Phylogenetic and biochemical characterization of the oil-producing yeast Lipomyces starkeyi

“…Several biochemical and physiological studies on this yeast have been performed, including the examination of the effects of media components, such as carbon sources, mineral ions, and culture temperature. These studies have shown that only a few trace elements influence the growth and lipid content of this yeast (Naganuma et al 1975(Naganuma et al , 1985a(Naganuma et al , 1985b1986;Suutari et al 1993;Zhao et al 2008). Moreover, it has been reported that some strains of this yeast converted not only glucose but also xylose to lipids (Fall et al 1984;Naganuma et al 1985b;Zhao et al 2008).…”

Screening for <i>Lipomyces</i> strains with high ability to accumulate lipids from renewable resources

“…Our laboratory has been carrying out research on the physiology, biochemistry and ecology of yeast Lipomyces (Naganuma et al, 1985(Naganuma et al, , 1986(Naganuma et al, , 1989(Naganuma et al, , 1999Watanabe et al, 1997). In these studies, we used deposit strains and strains isolated from Japanese soils.…”