Further improvements in culture growth may be obtained by appropriate modifications of the most suitable standard recipe. A modification of the LS medium (called M-S medium) resulted in a 15% improvement in cell dry weight yields from L. erythrorhizon cultures.
Biomass production can be markedly increased by the use of a larger inoculum size, to give higher initial cell density, in combination with proportionately enriched nutrient medium, e.g., twice the concentration of normal medium for a two-fold increased inoculum size, etc. Often suitable alterations in the medium composition have to be made, and fresh medium may have to be added at regular intervals for optimum biochemical/biomass yields.
In case of C. japonica cell cultures, four-times the normal inoculum (combined with x4 concentration modified medium) yielded 55 g cell dry weight/I as against 14 g/l from normal inoculum combined with normal concentration of the modified medium. However, the berberine yield remained almost constant at 3.5 g/l since the cells from higher inoculum size showed markedly lower berberine content.