title: Environmental stress and elicitors enhance taxol production by endophytic strains of Paraconiothyrium variabile and Epicoccum nigrum.
abstract: This study examined the effect of different elicitors (seven, different concentrations) and environmental factors (water activity (aw), pH) on taxol production by strains of two endophytic fungi, Paraconiothyrium variabile and Epicoccum nigrum, isolated from temperate yew trees. A defined liquid broth medium was modified with elicitors, solute aw depressors at different pH values. For P. variabile, the best elicitor was salicylic acid at 50mg/l which gave a taxol yield of 14.7±4.8μg/l. The study of synergistic effects between elicitor, aw and pH on taxol production showed that the highest yield of taxol (68.9±11.9μg/l) was produced under modified ionic stress of 0.98aw (KCl) at pH 5 when supplemented with 20mg/l of salicylic acid. For E. nigrum, serine was the best elicitor which increased yield significantly (29.6 fold) when KCL was used as the aw depressor (0.98aw) at pH 5.0 with 30mg/l of serine. The maximum taxol yield produced by E. nigrum was 57.1±11.8μg/l. Surface response models were used to build contour maps to determine the conditions for maximum and marginal conditions for taxol yield in relation to the best elicitor and aw, and the best pH for the first time. This will be beneficial for identifying key parameters for improvement of taxol yields by endophytic fungi.
authors.affiliation: Applied Mycology Group, AgriFood Theme, Cranfield University, Cranfield, Beds MK43 0AL, UK.
authors.forename: Supunnika
authors.initials: S
authors.lastname: Somjaipeng
authors.affiliation: Applied Mycology Group, AgriFood Theme, Cranfield University, Cranfield, Beds MK43 0AL, UK.
authors.forename: Angel
authors.initials: A
authors.lastname: Medina
authors.affiliation: Applied Mycology Group, AgriFood Theme, Cranfield University, Cranfield, Beds MK43 0AL, UK. Electronic address: n.magan@cranfield.ac.uk.
authors.forename: Naresh
authors.initials: N
authors.lastname: Magan
mesh_terms: D000972:Antineoplastic Agents, Phytogenic / Q000096:biosynthesis; D001203:Ascomycota / Q000187:drug effects / Q000302:isolation & purification / Q000378:metabolism*; D003470:Culture Media; D060026:Endophytes / Q000187:drug effects / Q000302:isolation & purification / Q000378:metabolism; D006863:Hydrogen-Ion Concentration; D017239:Paclitaxel / Q000096:biosynthesis*; D020156:Salicylic Acid / Q000494:pharmacology; D012694:Serine / Q000494:pharmacology; D013312:Stress, Physiological; D020946:Taxus / Q000382:microbiology
chemical_list: D000972:Antineoplastic Agents, Phytogenic; D003470:Culture Media; D012694:Serine; D020156:Salicylic Acid; D017239:Paclitaxel
keywords: Elicitors; Enhanced production; Growth; Pharma products; Taxol production; Water stress; pH