Mesoporous xerogel has been prepared by a non-surfactant sol-gel process to encapsulate living yeasts.Trehalose and glycerol are chosen as both the protective agents and pore-forming agents.Hydroxyethylcellulose (HEC)

an additive

is utilized to reduce the shrinkage of gel during drying process.The encapsulated yeasts survived in the xerogel and maintained the capability to assimilate glucose.The relationship between the yeast metabolic kinetics and the xerogel pore parameters was investigated.With tetraethoxysilane(TEOS) and methyl triethoxysilane (MTES) as precursors for reinforcing the material and transforming the hydrogel(60% moisture content) to xerogel(10%moisture content)

the leakage of the yeasts is partially prevented.Through the uniaxial compressive strength test

the strength of xerogel can reach 7.13 MPa at least

which is twelve times more than that of the hydrogels.According to plate count method

the concentration of yeasts was about 1.5?108 mL-1 in sol and 6.4?108 g-1 in xerogel.Through the characterization of the specific surface area

pore structure and the yeast metabolic kinetics

we found that the metabolic dynamics of entrapped yeast was related to the pore parameters of silica matrix.The xerogel obtained by non-surfactant process could have the specific surface area of 800 m2g-1

the pore volume of 0.44 cm3g-1 and the pore diameter of 2.7 nm.Under such conditions

calculated from independent samples without free yeasts

statistically

the encapsulated yeasts can metabolize 89% glucose of the culture medium in 60 h.