Staff Members - Benha University
Identification of Green Alga Chlorella vulgaris Isolated from Freshwater and Improvement Biodiesel Productivity via UV Irradiation.
Microbiology and Biotechnology Letters • 2019
Publication Information
Authors
Mohamed A. Gomaa; Mohamed H. Refaat; Tamer M. Salim; Abo El-Khair B. El-Sayed and Makhlouf M. Bekhit
Keywords
Chlorella vulgaris, 18S rRNA gene, UV irradiation, fatty acid, fuel properties
Journal
Microbiology and Biotechnology Letters
Publisher
The Korean Society for Microbiology and Biotechnology
Volume
47
Issue
3
Pages
381-389
publication.type
International
Paper Link
Open Link
Supplementary Materials
Not Available
Abstract
Chlorella vulgaris was isolated from the Nile River, Qalubia Governorate, Egypt, for possible use in biodiesel
production. BG-II nutrient growth media was used for isolation and laboratory growth. Identification
was performed via 18S rRNA gene amplification, followed by sequencing. The alga was exposed to UVC (254 nm) for 15, 30, and 45 s to improve dry weight accumulation and to increase the oil production. Daily
measurements of dry weight (g·l–1) were performed; oil content and volumetric lipid productivity were also determined. UV-C exposure led to an increase in the volumetric lipid productivity by 27, 27.3, and 32.4 mg·l-1·d-1
with 15, 30, and 45 s, respectively, as compared with the control, which resulted in 18 mg·l-1·d-1. Of the examined mutants, the one with the highest productivity was re-irradiated by UV-C (254 nm) for 15, 30, 45, and
60 s. For 15 s of exposure time, the oil content increased to 34%, while it was 31% at 30 s; further, it decreased to 22% at 45 and 60 s exposures. The fatty acid methyl ester profile was 82.22% in the first mutant
at 45 s, compared with the wild strain that contained a total of 66.01% of FAs. Furthermore, the highest levels of polyunsaturated fatty acid methyl ester were observed in the mutant exposed for 45 s, and it reached 11.41%, which reduced the cetane number to 71.3.
production. BG-II nutrient growth media was used for isolation and laboratory growth. Identification
was performed via 18S rRNA gene amplification, followed by sequencing. The alga was exposed to UVC (254 nm) for 15, 30, and 45 s to improve dry weight accumulation and to increase the oil production. Daily
measurements of dry weight (g·l–1) were performed; oil content and volumetric lipid productivity were also determined. UV-C exposure led to an increase in the volumetric lipid productivity by 27, 27.3, and 32.4 mg·l-1·d-1
with 15, 30, and 45 s, respectively, as compared with the control, which resulted in 18 mg·l-1·d-1. Of the examined mutants, the one with the highest productivity was re-irradiated by UV-C (254 nm) for 15, 30, 45, and
60 s. For 15 s of exposure time, the oil content increased to 34%, while it was 31% at 30 s; further, it decreased to 22% at 45 and 60 s exposures. The fatty acid methyl ester profile was 82.22% in the first mutant
at 45 s, compared with the wild strain that contained a total of 66.01% of FAs. Furthermore, the highest levels of polyunsaturated fatty acid methyl ester were observed in the mutant exposed for 45 s, and it reached 11.41%, which reduced the cetane number to 71.3.