Production and Screening of High Yield Avermectin B1b Mutant of Streptomyces avermitilis 41445 Through Mutagenesis

Abstract

Background:Secondary metabolite production from wild strains is very low for economical purpose therefore certain strain improvement strategies are required to achieve hundred times greater yield of metabolites. Most important strain improvement techniques include physical and chemical mutagenesis. Broad spectrum mutagenesis through UV irradiation is the most important and convenient physical method.Objectives:The present study was conducted for enhanced production of avermectin B1b from Streptomyces avermitilis 41445 by mutagenesis using ultraviolet (UV) radiation, ethidium bromide (EB), and ethyl methanesulfonate (EMS) as mutagens.Materials and Methods:S. avermitilis DSM 41445 maintained on yeast extract malt extract glucose medium (YMG) was used as inoculum for SM2 fermentation medium. Spores of S. avermitilis DSM 41445 were exposed to UV radiation for physical broad spectrum mutagenesis and to EMS and EB for chemical mutagenesis. For each mutagen, the lethality rate and mutation rate were calculated along with positive mutation rate.Results:Avermectin B1b-hyper-producing mutant, produced using these three different methods, was selected according to the HPLC results. The mutant obtained after 45 minutes of UV radiation to the spores of S. avermitilis 41445, was found to be the best mutant for the enhanced production of avermectin B1b component (254.14 mg/L). Other avermectin B1b-hyper-producing mutants, were obtained from EMS (1 µL/mL) and EB (30 µL/mL) treatments, and yielded 202.63 mg/L and 199.30 mg/L of B1b, respectively.Conclusions:The hereditary stability analysis of the UV mentioning 45 minutes revealed the UV exposure time for mutants and 3 represented the colony taken from the plate irradiated for 45 minutes mutant showed that the production of avermectin B1b remained constant and no reverse mutation occurred after 15 generations.

Avermectin Derivatives, Pharmacokinetics, Therapeutic and Toxic Dosages, Mechanism of Action, and Their Biological Effects

“…One of the commercially available forms of avermectin is abamectin, which contains 80% avermectin B1a and 20% avermectin B1b. It is reportedly to be used either as an insecticide or acaricide in several countries, mostly in countries that depend on agriculture and animal husbandry for preservation and protection, respectively [ 87 , 88 ]. In addition, Khalil et al [ 32 ] reported its use as a protective agent against plant nematodes that feed on the roots, during seed germination, coupled with its long shelf-life, while Hussein and Sabry [ 89 ] reported its molluscicides activity against matured E. vermiculata in the growth of wheat.…”

A comprehensive review of glycosylated bacterial natural products

“…33). 718–720 They are 16-membered macrolides produced by Streptomyces , Amycolatopsis and Nocardia . Avermectins typically contain a C-13 disaccharyl substitution (disaccharide VI ).…”

Random mutagenesis and process optimization of bacterial co-culture for hyperproduction of 1,4-α-D-glucan glucanohydrolase using submerged fermentation

“…Production of the enzyme from a wild strain is usually low. Therefore, strain improvement and optimization of culture conditions play a vital role in enhancing the enzyme production [23]. For this purpose, two Bacillus species Bacillus subtilis LCBT-15 and Bacillus amyloliquefaciens LCBT-20 were subjected to different mutagens such as UV light, ethidium bromide and EMS (30-120min) for better production of GGH.…”