title: Mass production of aphicidal Beauveria bassiana SFB-205 supernatant with the parameter of chitinase.
abstract: Beauveria bassiana SFB-205 supernatant can effectively control cotton aphid populations, which is closely associated with its chitinase activity. The present work extends to optimizing a culture medium to produce more efficacious supernatant in flask conditions, followed by scale-up in 7 L, 300 L and 1.2 KL fermentors with the parameter of chitinase. In flask conditions, a combination of soluble starch and yeast extract produced the greatest amount of chitinase (5.1 units/ml) and its supernatant had the highest aphicidal activity. An optimal quantitative combination of the two substrates, estimated by a response surface method, enabled the supernatant to have 15.7 units/ml of chitinase activity and 3.7 ml/l of median lethal concentration (LC50) of toxicity against cotton aphid adults in laboratory conditions. In the scale-up conditions, overall supernatant had 25-28 units/ml of chitinase activity. Decrease in pH and limitation of dissolved oxygen (DO) during cultures were significantly related to the yield of chitinase. These results suggest that the substrate-dependent chitinase production can be background information for optimizing a culture medium, and pH and DO are critical factors in maximizing the production in scale-up conditions.
authors.affiliation: Entomology Research Laboratory, Plant and Soil Science, University of Vermont, 661 Spear Street, Burlington, VT 05405-0105, USA.
authors.forename: Jae Su
authors.initials: JS
authors.lastname: Kim
authors.forename: Yeon Ho
authors.initials: YH
authors.lastname: Je
authors.forename: Yong-Man
authors.initials: YM
authors.lastname: Yu
mesh_terms: D000818:Animals; D001042:Aphids / Q000187:drug effects*; D052982:Beauveria / Q000201:enzymology / Q000254:growth & development* / Q000378:metabolism*; D001709:Biotechnology / Q000379:methods*; D002688:Chitinases / Q000096:biosynthesis* / Q000378:metabolism; D003470:Culture Media / Q000737:chemistry; D017077:Culture Media, Conditioned / Q000737:chemistry* / Q000494:pharmacology*; D005285:Fermentation; D003368:Gossypium / Q000469:parasitology; D006863:Hydrogen-Ion Concentration; D010100:Oxygen / Q000378:metabolism; D010572:Pest Control, Biological; D013379:Substrate Specificity
chemical_list: D003470:Culture Media; D017077:Culture Media, Conditioned; D002688:Chitinases; D010100:Oxygen