Improvement of selenium enrichment in Rhodotorula glutinis X-20 through combining process optimization and selenium transport

Abstract

Selenium-enriched yeast can transform toxic inorganic selenium into absorbable organic selenium, which is of great significance for human health and pharmaceutical industry. A yeast Rhodotorula glutinis X-20 we obtained before has good selenium-enriched ability, but its selenium content is still low for industrial application. In this study, strategies of process optimization and transport regulation of selenium were thus employed to further improve the cell growth and selenium enrichment. Through engineering phosphate transporters from Saccharomyces cerevisiae into R. glutinis X-20, the selenium content was increased by 21.1%. Through using mixed carbon culture (20 g L −1 , glycerol: glucose 3:7), both biomass and selenium content were finally increased to 5.3 g L −1 and 5349.6 µg g −1 (cell dry weight, DWC), which were 1.14 folds and 6.77 folds compared to their original values, respectively. Our results indicate that high selenium-enrichment ability and biomass production can be achieved through combining process optimization and regulation of selenium transport.

Accumulation of Selenium in Candida utilis Growing in Media of Increasing Concentration of this Element

“…Research presented by Wang et al [39] showed that Rhodotorula glutinis X-20 yeast grown in 30 mg Se 4+ /L supplemented medium is able to accumulate selenium at a level of 5349.6 μg/g after 36 h of cultivation. An interesting course of changes in the bioaccumulation of selenium in the cell biomass of Enterococcus durans LAB18s was presented by Pieniz et al [40].…”

Selenium (Se) recovery for technological applications from environmental matrices based on biotic and abiotic mechanisms

“…The transportation of SeO4 2and SeO3 2into cells is the first step of Se metabolism [200]. Transporters for structurally similar oxyanions, e.g., SO4 2and PO4 3-, can uptake Se oxyanions [201,202]. SeO4 2and SeO3 2can enter the E. coli cells through the sulphate permease system (cysA, cysU, cysW) [203,204].…”

“…SeO4 2and SeO3 2can enter the E. coli cells through the sulphate permease system (cysA, cysU, cysW) [203,204]. Through engineering PO4 3-transporters from Saccharomyces cerevisiae into Rhodotorula glutinis X-20, Se content in the cell was increased by 21.1% and reached 5349.6 µg g -1 with SeO3 2as the Se source [202]. However, the Se uptake pathway is not well documented, and no specific Se oxyanions uptake system has been reported.…”

Carotenoid Biosynthesis: Genome-Wide Profiling, Pathway Identification in Rhodotorula glutinis X-20, and High-Level Production

“…In addition, R. glutinis can achieve the purpose of improving the soil environment by adsorbing heavy metal elements (10). Even, we have screened a selenium-rich R. glutinis that is beneficial to the human body after converting inorganic selenate to organic selenic acid (11). Because R. glutinis can be cultivated from low-value raw materials and can create industrialized products through highefficiency transformation processes, increasing researches are focusing on analyzing the reasons for its multiple applications by mining and verifying the genomic information (12,13).…”

“…Previously, R. glutinis X-20 was screened from a seleniumenriched soil on the northern slopes of the Tianshan Mountains in Xinjiang Province, China, showing a high selenium-enriched capacity with 5,349.6 µg•g −1 DWC (11). And also, it can generate large levels of β-carotene and lipids.…”