Mutation Breeding Of The Nannochloropsis Oceanica And The Screening Technique Of The Microalgae Rich In Lipid

Along with the development of the world economy, fossil energy consumptionincreasing, the environment problems continue to highlight. In order to promote thesustainable economic and social development, we must speed up the transformationdevelopment way to optimize the energy structure, the development of resourceconservation environmental friendly new energy.Microalgae are the the primaryproducers of the water and the ecological system, with the characteristic such asvarious kinds of simple structure growth rapidly and oil content higher. In recentyears, the use of micro algae preparation of biodiesel has become the focus ofresearch around the world. However, due to various reasons, microalgae biodieselpreparation still failed to realize industrialized production, and excellent germplasmresources are micro algae biodiesel industrialization production base.Nannochloropsisoceanica can growth speedly.The algae has high oil content and strong resistance,which is a good algae of great development potential.This paper intends to use the microalgae (Nannochloropsis oceanica) as theexperimental material.The laboratory saved Nannochloropsis oceanica (Numbered for179)was treated with two times purification to get the pure single kind of the algalstrain as the starting algae strains, mainly for the following research:The applicability of herbicide quizalofop-p-ethyl to the screening of lipid-richmicroalgae was determined in this study.It was found that7.5mol/L ofquizalofop-p-ethyl (final concentration in medium) could inhibit the growth of99.7%N. oceanica cells and10mol/L of quizalofop-p-ethyl could inhibit the growth of N.oceanica completely. Two quizalofop-p-ethyl resistant strains of N. oceanica, KA1andKA2, were obtained on f/2medium containing7.5mol/L quizalofop-p-ethyl.When cultured for52days, The total lipid of KA1andKA2increased by29.02%and 6.57%, respectively, over that of the original strain, reaching46.73%and38.60%ofdry weights, respectively. The specific growth rate and the final dry biomass ofscreened algal strains KA1were not significantly different from the original algalstrain, but the oil productivity of KA1were higher than that of the original algalstrain.This research use concentration of fifty mM EMS to the microalgae on mutagenictreatment, and quizalofop-p-ethyl as a screening pressure on lipid rich mutagenicalgal strain screening.We get two strains of high lipid which is numbered withKE75B1and KE10A1. Its total fat content of cell dry weight were44.19%and43.51%, compared to the start algae strains (total fat of dry weight percentage is39.34%) increased by12.35%and10.62%respectively (P <0.05), and oil productionrate of the algae strain KE75B1is also improved significantly by18.07%compared tothe start algae strains.This study explores the effectiveness of the high throughput screening method bythe Nile red microwave assisted dyeing in lipid rich microalgae screening. The resultsindicate that the best microwave heating time were45s and15s in the Nile reddyeing. Through the high throughput screening method,we got three lipid rich algaestrains. The total fat in the cells have increased compared with the start algae strains.When verified by the method of chloroform–methanol extracted, the total fat in theE232and E234increased13.01%and16.39%（P<0.05），separately. Although,theincreasing of the total fat in the strains E225was not significant (P>0.05), the total fat inE225increased10.78%.It proved the feasibility of the high-throughput screeningmethod.To sum up, this research proves that the effectiveness of EMS mutation breeding inlipid rich microalgae.Pure the herbicide quizalofop-p-ethyl was determined as a goodscreening method of high fat microalgae.It has proven the basic conditions of the Nilered microwave assisted dyeing.This paper provides reference for the development of the mutation breeding of microalgae.