UV Mutagenesis as a Strategy to Enhance Growth and Lipid Productivity of <i>Chlorella</i> sp. 042

Abstract

Microalgae appeared to be an alternative feedstock for renewable biodiesel production due to their capability to accumulate considerable amounts of lipids. In this study, mutagenesis using UVC light with different periods was applied to Chlorella sp. 042 to produce a microalgae strain with high lipid productivity of 45, 60, and 75 min. The Nile red fluorescence method was conducted to select a Chlorella sp. mutant with high neutral lipid and generated one mutant from every UV mutation period, M45-06, M60-02, and M75-21. All of the mutants have higher growth rates than the wild type. Chlorella sp. 042 M60-02 achieved the highest lipid productivity, with 34 mg L-1 day-1. Furthermore, as other major biochemical components, carbohydrate and protein contents were determined. Our results showed that all the mutants enhance their carbohydrate and protein contents compared to the wild type. However, mutations for more than 60 min do not intensely change the protein content of mutant microalgae. Gas chromatography-mass spectrophotometry analysis revealed that M60-02 mutant has similar FAME profiles with the wild type, which contain palmitic acid (C16:0), stearic acid (C 18:0), oleic acid (C18:1), and linoleic acid (C18:2). These results demonstrate that the UV mutation of Chlorella sp. 042 for 60 min is suitable as a source of biodiesel production.

Sustainable Production of Biodiesel Using UV Mutagenesis as a Strategy to Enhance the Lipid Productivity in R. mucilaginosa

“…The percentage of lipids produced from the biomass of the wild strain and the mutant strain was analyzed and the amount of lipids extracted from the wild strain was noted as 41.3%, whereas the mutant strains of M30-8, M75-24, and M90-18 produced 68.5%, 56.3%, and48.6% of lipids, respectively, at the exponential phase of the culture. Similarly, to our study Rike Rachmayati et al (2020) [14] also found a gradual increase in the growth of biomass in UV-mutated Chlorella sp., compared to the growth of biomass in the wild strain, and Liu et al ( 2015) [28] have shown high lipid content in UV mutagenized microalgal species compared to the lipid content produced by wild strain. Therefore, UV mutation shows an increase in ACC concentration that enhances lipids.…”

“…Similarly, to our study Rike Rachmayati et al (2020) [14] also found a gradual increase in the growth of biomass in UV-mutated Chlorella sp., compared to the growth of biomass in the wild strain, and Liu et al (2015) [28] have shown high lipid content in UV mutagenized microalgal species compared to the lipid content produced by wild strain. Therefore, UV mutation shows an increase in ACC concentration that enhances lipids.…”

“…The mutated strains were sequenced to analyze the homology difference with wild strain VS3. Similarly, Rike Rachmayati et al (2020) [14] have screened high lipidyielding microalgae by using Nile red fluorescence staining to analyze wild and UV-mutated strains, while Chen et al (2009) [27] have applied the Nile red staining method to identify the lipid content present in oleaginous micro-organisms, and Halim et al (2015) [26] have shown that Nile red stain emits fluorescence when it interacts with lipids present in the microbial bodies. Hence, Nile red staining is used to screen high lipid-yielding microbes from the UV-mutated strain.…”

“…The radioactive waves produced from UV radiation damage DNA by producing covalent linkages between adjacent pyrimidine bases. The pyrimidine dimer produced from the covalent linkage is not capable of fixing in the double-strand structure of DNA, causing replication and translation to become inhibited [14]. Typically, the formation of dimer results in a deletion of base pairs, causing mutation to occur, whereas other types of radiation can have different effects on mutation depending on their wavelength and the intensity of radiation, but mainly mutations occur in the process of insertion and deletions of DNA base pairs [15].…”

Edible and medicinal fungi breeding techniques, a review: Current status and future prospects

“…The capacity to undergo mutation is an inherent property of genetic material, including both the genes themselves and also the chromosomes on which the genes are arranged linearly in a certain order ( Obe et al, 1971 ). Various traditional mutagenic sources, such as chemical mutagens, physical mutagens as UV-rays ( Rachmayati et al, 2020 ), γ-rays ( Hidayati et al, 2021 ), and the N + ion beam (C. Wang et al, 2012 , Wang et al, 2012 ), have been developed and successfully applied to acquire valuable strains.…”