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Taking simulated sunlight as abiotic environmental stress condition, the fermentation conditions of carotenoid synthesis by Rhodotorula glutinis were optimized by single factor test and orthogonal test. The effects of hight stress on growth of Rhodotorula glutinis and carotenoid synthesis were studied. The results showed that the light intensity of 5000 Lux could significantly increase the biomass and carotenoid yield. The type of carbon sources had the greatest effect on carotenoid biosynthesis. Glycerol and glucose could be better used to synthesize carotenoids. The optimal fermentation conditions were glycerol concentration of 20 g/L, yeast powder addition of 3.5 g/L, the initial pH value 5.0 and temperature of 25 °C. After cultured in 5 L fermentor for 144 h, the biomass and carotenoid yield reached 14.2 g/L and 17.3 mg/L, respectively, which were 24. 5% and 21.0% higher than those before optimization; Light stress could not only increase the yield of carotenoids, but also effectively increase the proportion of high value-added carotenoids (torularhodin and torulene) in the product. [ABSTRACT FROM AUTHOR]

Constructing S-scheme heterojunction photocatalysts reveals a greatly improved separation efficiency of photogenerated carriers and enhanced harvesting ability of solar energy in photocatalytic field. Herein, a ternary CdS-g-C 3 N 4 -GA heterojunction has been fabricated by a facile ultrasound strategy, which behaved as a S-scheme heterojunction with an intimate interface formed, and GA played as an electronic transportation platform to promote the separation of photo-induced charge carriers, which was certified through photoelectrochemical techniques. Density functional theory calculations revealed that the different component in ternary CdS-g-C 3 N 4 -GA heterojunction demonstrated an obvious difference of work function, resulting in the charge transfer from CdS to g-C 3 N 4 through GA with S-scheme principle. In the optimized conditions, the S-scheme CdS-g-C 3 N 4 -GA heterojunction not only displayed greatly enhanced photocatalytic performances for degradation of dye and antibiotic wastewater, but also improved photocatalytic H 2 production activity. In addition, the photocatalytic mechanism and driving force of charge transfer and separation in S-scheme CdS-g-C 3 N 4 -GA heterojunction were studied. This study offers a feasible strategy to construct a ternary S-scheme heterojunction for environmental and energy photocatalysis., (Copyright © 2021 Elsevier Inc. All rights reserved.)