The effect of microdosimetric 12C6+ heavy ion irradiation and Mg2+ on canthaxanthin production in a novel strain of Dietzia natronolimnaea

Abstract

BackgroundDietzia natronolimnaea is one of the most important bacterial bioresources for high efficiency canthaxanthin production. It produces the robust and stable pigment canthaxanthin, which is of special interest for the development of integrated biorefineries. Mutagenesis employing 12C6+ irradiation is a novel technique commonly used to improve microorganism productivity. This study presents a promising route to obtaining the highest feasible levels of biomass dry weight (BDW), and total canthaxanthin by using a microdosimetric model of 12C6+ irradiation mutation in combination with the optimization of nutrient medium components.ResultsThis work characterized the rate of both lethal and non-lethal dose mutations for 12C6+ irradiation and the microdosimetric kinetic model using the model organism, D. natronolimnaea svgcc1.2736. Irradiation with 12C6+ ions resulted in enhanced production of canthaxanthin, and is therefore an effective method for strain improvement of D. natronolimnaea svgcc1.2736. Based on these results an optimal dose of 0.5–4.5 Gy, Linear energy transfer (LET) of 80 keV μm-1and energy of 60 MeV u-1 for 12C6+ irradiation are ideal for optimum and specific production of canthaxanthin in the bacterium. Second-order empirical calculations displaying high R-squared (0.996) values between the responses and independent variables were derived from validation experiments using response surface methodology. The highest canthaxanthin yield (8.14 mg) was obtained with an optimized growth medium containing 21.5 g L-1 D-glucose, 23.5 g L-1 mannose and 25 ppm Mg2+ in 1 L with an irradiation dose of 4.5 Gy.ConclusionsThe microdosimetric 12C6+ irradiation model was an effective mutagenic technique for the strain improvement of D. natronolimnaea svgcc1.2736 specifically for enhanced canthaxanthin production. At the very least, random mutagenesis methods using 12C6+ions can be used as a first step in a combined approach with long-term continuous fermentation processes. Central composite design-response surface methodologies (CCD-RSM) were carried out to optimize the conditions for canthaxanthin yield. It was discovered D-glucose, Mg2+ and mannose have significant influence on canthaxanthin biosynthesis and growth of the mutant strain.

Significance of Heavy-Ion Beam Irradiation-Induced Avermectin B1a Production by EngineeredStreptomyces avermitilis

“…The extraction time of the 12 C 6+ heavy ions (approximately 140 AMeV, 180 AMeV, and 220 AMeV of energy) was approximately 3 s, the priming dose was 80 Gy, and the dose rates were up to 10 Gy/min. In this study, the operating parameters were as follows: the radiation energy input was 140, 180, and 220 AMeV; the temperature of the 12 C 6+ heavy-ion beams was <35°C under these conditions [ 30 , 31 ].…”

Radiation induces acid tolerance of Clostridium tyrobutyricum and enhances bioproduction of butyric acid through a metabolic switch

“…Dose rates were up to 1.0 Gy·min -1 . For irradiation experiments, strains cell were grown in flasks (15 cm 2 ) to reach 90% confluence and they were completely filled with Dulbecco's modified Eagle's medium to avoid artifacts by irradiation through air layers [ 92 ]. The protocol is adapted from literature methods [ 93 ].…”

A Series of Efficient Umbrella Modeling Strategies to Track Irradiation-Mutation Strains Improving Butyric Acid Production From the Pre-development Earlier Stage Point of View

“…Butyric acid was previously produced through the oxidation of butyraldehyde [CH 3 (CH 2 ) 2 CHO] ( Henstra et al, 2007 ; Dagaut et al, 2009 ; Jin et al, 2011 ). However, customers tend to choose food additives, flavors as well as fragrances containing natural ingredients ( Ragauskas et al, 2006 ; Nigam and Singh, 2011 ; Zhou et al, 2013a , b ).…”