Mutagenesis breeding of high echinocandin B producing strain and further titer improvement with culture medium optimization

Abstract

A combination of microbial strain improvement and statistical optimization is investigated to maximize echinocandin B (ECB) production from Aspergillus nidulans ZJB-0817. A classical sequential mutagenesis was studied first by using physical (ultraviolet irradiation at 254 nm) and chemical mutagens (lithium chloride and sodium nitrite). Mutant strain ULN-59 exhibited 2.1-fold increase in ECB production to 1583.1 ± 40.9 mg/L when compared with the parent strain (750.8 ± 32.0 mg/L). This is the first report where mutagenesis is applied in Aspergillus to improve ECB production. Further, fractional factorial design and central composite design were adopted to optimize the culture medium for increasing ECB production by the mutant ULN-59. Results indicated that four culture media including peptone, K2HPO4, mannitol and L-ornithine had significant effects on ECB production. The optimized medium provided another 1.4-fold increase in final ECB concentration to 2285.6 ± 35.6 mg/L compared to the original medium. The results of this study indicated the combined application of a classical mutation and medium optimization can improve effectively ECB production from A. nidulans and could be a promising tool to improve other secondary metabolites production by fungal strains.

Genomics‐driven discovery of a novel self‐resistance mechanism in the echinocandin‐producing fungus Pezicula radicicola

“…Fermentation and extraction of wild type and Dprnrps4 strains of P. radicicola for HPLC-MS analysis Medium VI, which is the optimized medium for echinocandin production (Zou et al, 2015), and YM (1% malt extract, 0.2% yeast extract) were prepared to detect the production of sporiofungin in wild-type strain of P. radicicola. Wild-type strain was inoculated in medium VI or YM to prepare seed cultures for 5 days at 220 r.p.m.…”

Integrated strategy of temperature shift and mannitol feeding for enhanced production of echinocandin B by Aspergillus nidulans CCTCC M2012300

“…However, the ECB productivity of whole batch fermentation remained relatively low because of the low level of mannitol that remained in ECB synthesis phase, which could have led to the insufficiency of carbon source. On the other hand, a high initial mannitol concentration had an inhibitory effect on cell growth and ECB production (Zou et al 2015b;Tóth et al 2012). A fed-batch fermentation process may relieve the above problem by controlling the substrate concentration below the inhibitory levels (Dolejs et al 2014;Le Meur et al 2014).…”

“…Recently, two-stage control strategies have been widely applied in many fermentations of desired metabolites (Si et al 2017;Wang et al 2016;Dias et al 2015;Ying et al 2014;Zheng et al 2013). Previous studies on ECB production addressed the optimization of the medium composition (Tóth et al 2012;Cockshott and Sullivan 2001;Cockshott and Hartman 2001) or focused on strain screening (Zou et al 2015b;Hu et al 2016). However, no reports have been made on the effects of a temperatureshift strategy on ECB fermentation.…”

“…In our previous work, a wild-type Aspergillus nidulans was treated with random mutagenesis and several high ECBproducing mutants were obtained (Zou et al 2015b). This work aims to establish an efficient fermentation process to improve the productivity and efficiency of ECB production by Aspergillus nidulans CCTCC M2012300.…”

Analysis of Morphological Features and Flavonoid Compositions of Crabapple Exposed to 60Coγ Radiation Treatments

“…Over the past thirty years, 60 Coγ has often been used for radiation breeding, production stimulation, pest control and food preservation, among other applications. The action of 60 Coγ radiation in plants always results in an improved mutation rate that expands the spectrum of mutations and induces new characteristics and rare types or mutations that do not exist in nature; this approach overcomes the hybrid incompatibility of distant source (Zou et al, 2015). One study showed that the seed germination of groundnut (Arachis hypogaea L.) was increased by 10-25% at lower doses of 60 Coγ radiation, and the improvement in plant vigor in the same dose range was much higher (22-84%) than that in the control without radiation (Ahuja et al, 2014).…”