<span style="font-size:11.0pt;font-family: "Times New Roman","serif";mso-fareast-font-family:"Times New Roman";mso-bidi-font-family: Mangal;mso-ansi-language:EN-GB;mso-fareast-language:EN-US;mso-bidi-language: HI" lang="EN-GB">Optimization of inoculum density in hairy root culture of <i style="mso-bidi-font-style:normal">Plumbago rosea</i> L. for enhanced growth and plumbagin production towards scaling-up in bioreactor</span>

Abstract

264-269<span style="font-size:11.0pt;font-family: " times="" new="" roman","serif";mso-fareast-font-family:"times="" roman";mso-bidi-font-family:="" mangal;mso-ansi-language:en-gb;mso-fareast-language:en-us;mso-bidi-language:="" hi"="" lang="EN-GB">The present study evaluated the influence of initial inoculum density (ID) on growth and plumbagin production in hairy root culture of Plumbago rosea L. in shake-flask as well as air-sparged bioreactor. IDs ranging from that of single root tip (0.08 g/L) to 10 g/L were analyzed in 50 mL MS basal media of 250 mL Erlenmeyer flasks. For scaling-up in bioreactor of 2 L working-capacity, 0.5, 1, 5, 10 and 15 g/L IDs were analysed. Optimal ID was found to be 1 g/L in shake-flask culture, producing a growth index of 36.15 on 30th d with plumbagin content of 1.325 g in 100 g DW of roots (1.325%). In the bioreactor, biomass increase was maximum for 5 g/L with a growth index of 11.428 and plumbagin content of 1.425%. Here we report the maximum plumbagin concentration (1.325%) in P. rosea hairy root culture, enhanced from 0.99% innate plumbagin content of the mother culture through sole optimization of ID. Further enhancement to 1.425% was attained by scaling-up in the bioreactor. The plumbagin concentration obtained in bioreactor culture of <i style="mso-bidi-font-style: normal">P. rosea hairy roots (1.425%) is also the highest reported so far in scaling-up. Thus results indicate that ID is a critical parameter influencing enhanced production of root biomass and plumbagin in hairy root cultures of P. rosea.</span