Carotenoids are natural pigments widespread in plants, some animals, fungi, and photosynthetic or nonphotosynthetic bacteria [1]. Their antioxidant activities have also been extensively studied [2]. Carotenoids have interesting biological functions including antioxidant, anticancer, and anti-obesity effects and are widely used in foods, nutraceuticals, and the feed industry [3]. Structurally, carotenoids can be divided into carotenes (e.g., α-/βcarotene and lycopene) and xanthophylls (e.g., lutein, zeaxanthin, fucoxanthin, and astaxanthin) [3]. Several types of carotenoids are produced by microorganisms. The yeast Xanthophyllomyces dendrorhous (Phaffia rhodozyma) produces astaxanthin [4], and microalgae produce lutein [5]. The fungus Blakeslea trispora has been reported to produce β-carotene and lycopene [6]. Lactic acid bacteria (LAB) are a type of gram-positive bacteria that are generally recognized as safe (GRAS) and have had diverse applications in fermentation of various foods for many centuries [7, 8]. LAB exhibit microaerophilic or facultative anaerobic growth characteristics owing to their lack of catalase expression and inability to remove free radicals [8]. To overcome this problem, LAB produce various antioxidants, such as superoxide dismutase and thioredoxin reductase [8, 9]. Moreover, LAB are known to produce carotenoids as a strategy for eliminating reactive oxygen species [10, 11]. The yellow pigment produced by

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IntroductionCarotenoids, natural pigments belonging to the isoprenoid group, exhibit yellow, orange, red, and purple colors and naturally occur in algae, yeasts, fungi, bacteria, and plants [1,2]. Carotenoids have various functions that are beneficial to human health; hence, they have been widely applied in the food, cosmetic, and pharmaceutical industries [1,2]. Representatively, they have antioxidant, anticancer, and antimicrobial activity, as well as immune regulatory functions [2].Recently, scientific interest related to carotenoid production using microorganisms has been increasing. Microbial pigments are a better alternative to synthetic or plant pigments because of their safety, availability, nonseasonality, scalability, high yield, and reduced process [2]. Most carotenoids found in bacteria consist of eight isoprene units with a 40-carbon structure (tetraterpenoids, C 40 carotenoids) such as astaxanthin, lycopene, and βcarotene. However, triterpenoids (C 30 carotenoids) have been reported to be found only in several bacterial species, such as Lactobacillus plantarum, Enterococcus faecium, Staphylococcus aureus, Methylobacterium rhodinum, and some heliobacteria [3].Carotenoids, which have biologically beneficial effects and occur naturally in microorganisms and plants, are pigments widely applied in the food, cosmetics and pharmaceutical industries. The compound 4,4′-diaponeurosporene is a C 30 carotenoid produced by some Lactobacillus species, and Lactobacillus plantarum is the main species producing it. In this study, the antioxidant activity of 4,4′-diaponeurosporene extracted from L. plantarum subsp. plantarum KCCP11226 was examined. Maximum carotenoid content (0.74 ± 0.2 at A 470 ) was obtained at a relatively low temperature (20°C). The DPPH radical scavenging ability of 4,4′-diaponeurosporene (1 mM) was approximately 1.7-fold higher than that of butylated hydroxytoluene (BHT), a well-known antioxidant food additive. In addition, the ABTS radical scavenging ability was shown to be 2.3-to 7.5-fold higher than that of BHT at the range of concentration from 0.25 mM to 1 mM. The FRAP analysis confirmed that 4,4′diaponeurosporene (0.25 mM) was able to reduce Fe 3+ by 8.0-fold higher than that of BHT. Meanwhile, 4,4′-diaponeurosporene has been confirmed to be highly resistant to various external stresses (acid/bile, high temperature, and lysozyme conditions). In conclusion, L. plantarum subsp. plantarum KCCP11226, which produces 4,4′-diaponeurosporene as a functional antioxidant, may be a potentially useful strain for the development of functional probiotic industries.

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