Production and optimization of carotenoid-enriched dried distiller’s grains with solubles by Phaffia rhodozyma and Sporobolomyces roseus fermentation of whole stillage

Abstract

Whole stillage--a co-product of grain-based ethanol--is used as an animal feed in the form of dried distiller's grain with solubles (DDGS). Since animals cannot synthesize carotenoids and animal feed is generally poor in carotenoids, about 30-120 ppm of total carotenoids are added to animal feed to improve animal health, enhance meat color and quality, and increase vitamin A levels in milk and meat. The main objective of this study was to produce carotenoid (astaxanthin and β-carotene)-enriched DDGS by submerged fermentation of whole stillage. Mono- and mixed cultures of red yeasts, Phaffia rhodozyma (ATCC 24202) and Sporobolomyces roseus (ATCC 28988), were used to produce astaxanthin and β-carotene. Media optimization was carried out in shake flasks using response surface methodology (RSM). Macro ingredients, namely whole stillage, corn steep liquor and glycerol, were fitted to a second-degree polynomial in RSM. Under optimized conditions, astaxanthin and β-carotene yields in mixed culture and P. rhodozyma monoculture were 5 and 278, 97, and 275 μg/g, respectively, while S. roseus produced 278 μg/g of β-carotene. Since the carotenoid yields are almost twice the quantity used in animal feed, the carotenoid-enriched DDGS has potential application as "value-added animal feed or feed blends."

Nutrient recovery from ethanol co-products by a novel mycoalgae biofilm: attached cultures of symbiotic fungi and algae

“…Fungal based systems can be relatively easy to harvest compared with algae‐based processes. In terms of feeding value, algae have specific bioactive compounds like carotenoids, polyunsaturated fatty acids, vitamins, immunostimulants, and antioxidants which are beneficial for animal growth …”

From Cheese Whey to Carotenes by Blakeslea trispora in a Bubble Column Reactor

“…Mantzouridou et al [14] found that a maximum productivity of carotenes (9.4 and 29.4 mg/g dry biomass/day) was obtained when B. trispora was grown in crude olive pomace oil and crude soybean oil, respectively. The maximum carotene productivity was 0.03-2.9 mg/g dry biomass/day (0.2-16.5 mg/l/day) when several agro-industrial by-products such as whole stillage, corn steep liquor, parboiled rice water, hydrolyzed mung bean waste flour, grape must, fermented radish brine, crude glycerol, wheat straw, grape juice, and molasses were used as substrates for carotene production by Phaffia rhodozyma, Sporobolomyces roseus, Sporidiobolus pararoseus, Cystofilobasidium capitatum, R. glutinis, R. mucilaginosa, recombinant industrial wine yeast, and Arthrobacter globiformis in shake flask culture and stirred tank fermentor [1,5,[15][16][17][18][19][20][33][34][35]. The cited results show that the amounts of carotenes produced from different agro-industrial by-products were very low compared with our results, that is, 55.5 mg/g dry biomass/day (405.0 mg/l/day) using bubble column reactor and deproteinized hydrolyzed whey supplemented with Tween 80, Span 80, and β-ionone.…”

“…However, utilization of a synthetic medium is not economical and the exploitation of a less expensive medium could prove beneficial. Numerous agro-industrial by-products such as crude olive pomace oil, crude soybean oil, whole stillage, grape juice, grude glycerol, wheat straw, parboiled rice water, corn steep liquor, and molasses have been considered as potential carbon sources for biotechnological production of carotenes by different strains of fungi, yeasts, and bacteria [5,[14][15][16][17][18][19].…”

Astaxanthin synthesis by Xanthophyllomyces dendrorhous DSM 5626 and its astaxanthin overproducing mutants on xylose media under diferent illumination

“…Ananda and Vadlani [2010] considered high viscosity of the culture medium, leading to lower diffusion of oxygen, to have been the cause of this result. When running 5-day cultures of Phaffi a rhodozyma ATCC 24202 (the parental strain used in this study) on media containing whole maize stillage they obtained a very low yield of astaxanthin (0.026 μg·g -1 of freeze-dried stillage), while β-carotene was the primary pigment produced by P. rhodozyma.…”

“…They may utilise different carbon substrates: glucose, maltose, sucrose, cellobiose, xylose, arabinose, lactose and many other, frequently unconventional sources [Palágyi et al 2001]. Literature data show that higher yields of astaxanthin with X. dendrorhous yeast are obtained on media containing xylose than on media containing glucose or other carbon substrates [Vazquez et al 1997, Ananda and Vadlani 2010.…”