Leuconostoc mesenteroides growth kinetics with application to bacterial profile modification

Abstract

Bacterial profile modification (BPM) is being developed as an oil recovery technique that uses bacteria to selectively plug oil depleted zones within a reservoir to divert displacing fluids (typically water) into oil-rich zones. Leuconostoc mesenteroides, which produces dextran when supplied with sucrose, is a bacterium that is technically feasible for use in profile modification. However, the technique requires controlled bacterial growth to produce selective plugging.A kinetic model for the production of cells and polysaccharides has been developed for L. mesenteroides bacteria. This model, based on data from batch growth experiments, predicts saccharide utilization, cell generation, and dextran production. The underlying mechanism is the extracellular breakdown of sucrose into glucose and fructose and the subsequent production of polysaccharide (dextran). The monosaccharides are then available for growth. Accompanying sucrose consumption is the utilization of yeast extract. The cell requires a complex media that is provided by yeast extract as a source of vitamins and amino acids. Varying the concentration ratio of yeast extract to sucrose in the growth media provides a means of controlling the amount of polymer produced per cell. Consequently, in situ bacteria growth can be controlled by the manipulation of nutrient media composition, thereby providing the ability to create an overall strategy for the use of L. mesenteroides bacteria for profile modification.

Biomass evolution in porous media and its effects on permeability under starvation conditions

“…b Estimated using batch experimental data (Lappan and Fogler, 1994). experimental data, in Figure 10.…”

Effects of pH and Trace Minerals on Long-Term Starvation ofLeuconostoc mesenteroides

“…The sucrose-induced enzyme dextransucrase breaks down sucrose into glucose and fructose and links the glucose molecules into dextran. The cell growth on sucrose was reported to be virtually the same as the cell growth on the stoichiometrically equivalent mixture of glucose and fructose (25). The kinetics of cell growth and enzyme and exopolymer production have been well studied in our laboratory and can be found elsewhere (19,25).…”

“…The species L. mesenteroides is classified as a member of the lactobacilli, which are gram positive. It is spherical (0.5 to 1.2 m in diameter), forms long chains during growth, is an oxygen-tolerant anaerobe, and it is known to produce extracellular polysaccharides when fed sucrose (20,22,25). The sucrose-induced enzyme dextransucrase breaks down sucrose into glucose and fructose and links the glucose molecules into dextran.…”

Permeability profile modification using bacterially formed calcium carbonate: comparison with enzymic option

“…Injected water preferentially flows through the areas of high permeability, thus the residual oil in the region of low permeability is by-passed and remains unrecovered [3,4]. Selective plugging of reservoir rock by microbial biomass and extracellular biopolymers produced by microbial cells has been suggested as an efficient way for profile modification and improving the sweeping efficiency of the injected fluids [1,3,5,6]. In addition, some species of bacteria have the ability to accumulate or induce the formation and precipitation of various inorganic compounds, such as Nomenclature Q flow rate of the fluid (m 3 /h) K porous medium permeability (m 2 ) A cross-sectional area of porous medium (m 2 ) P pressure difference (kPa) η viscosity (kg/m h) L depth of the porous medium (m) K f porous medium permeability after formation of CaCO 3 (m 2 ) K i initial permeability of porous medium (m 2 ) Q f flow rate after formation of CaCO 3 (m 3 /h) Q i initial flow rate (m 3 /h) phosphates, carbonates and silicates, which could contribute to plugging of high permeability regions in the reservoir [7].…”