Abstract:

A commercial sample of lentinans was refined and subjected to ethanol fractionations in two different ways: way No.1, use of ethanol concentration gradients of 10%, 20%, 30% to 90%, respectively, and way No.2, adjustment of ethanol concentration in supernatant to 10%, 20%, 30% to 90% to understand molecular weight distribution by gel filtration chromatography. Results showed that precipitation time had no notable effect on the precipitation mass of lentinans and precipitation rate exhibited a gradual decrease with prolonged precipitation time. A maximum precipitation mass of lentinans was obtained at 30% ethanol concentration in way No. 2 precipitation. With increasing ethanol concentration, the precipitation mass of lentinans progressively increased in way No.1 precipitation and then trended nearly stable after reaching a high level. The peak molecular weight (Mp) of lentinans obtained at the ethanol concentrations of 30%, 50% and 80% were 22671, 18649 D and 6011D, respectively. In summary, both ethanol concentration and precipitation way had significantly effects on the precipitation mass and molecular weight distribution of lentinans

Key words: lentinan, ethanol precipitation, molecular weight, GPC