Carotenoids production by Paracoccus bogoriensis and their recovery using edible oils

Abstract

Carotenoids are widely used in nutrition, food, feed and pharmaceutical industries. Much attention has been given to caratenoids production and recovery from natural sources. Paracoccus bogoriensis, a microorganism isolated from Lake Bogoria, has been shown to be a potential source of natural carotenoids. This study was aimed at investigating production of carotenoids by Paracoccus bogoriensis and assessing carotenoids recovery using edible oils. To achieve this objective, the effect of cell lysis method, temperature and ethanol as co-solvent on extraction of carotenoids from Paracoccus bogoriensis using sunflower oil was tested. The recovery of carotenoids in soya, sunflower, corn, peanut, sesame and olive oil was evaluated spectrophotometrically under the optimal conditions. Production of carotenoids by Paracoccus bogoriensis in an inexpensive media made up of amaranth grain and sorghum flour was tested. The potential of semi industrial production of carotenoids was evaluated by assessing the effect of batch volume size on growth of Paracoccus bogoriensis. It was shown that cell lysis with Tween 20, Triton X-IOO and proteinase K was more effective than Iysozome, EDT A, urea, sand and their combinations in terms of total carotenoids released. Addition of ethanol as co-solvent at 15 % vlv, was adequate to give an optimal carotenoids yield of 611.18 ug/g cell in sunflower oil. The optimal temperature for carotenoids extraction in sunflower oil was 70°C at an incubation period , of 10 h. The yield of carotenoids in soy, sunflower, corn, peanut, olive and sesame oil was 320.2,.314.8,308.9,302.3,267.6 and 259.2 Ilg1 g cells respectively. Optimal growth of Paracoccus bogoriensis was in two media constituted by incorporating 0.5 % w/v amaranth grain flour and 0.75 % w/v sorghum flour ng 0.5 % w/v amaranth grain flour and 0.75 % w/v sorghum flour in Lauria bartani (LB) basal medium respectively. The optimal addition yielded 4.5 gil and 4.1 g/l, which was equivalent to 36.4 % and 24.2% increase in Paracoccus bogoriensis biomass respectively. The biomass yield in LB broth and LB+ 1 % (w/v) starch at 100mi batch was 3.6 g/l and 4.08 g/l, 500 ml batch was 3.14 g/I and 3.45 g/l and 1000 ml batch was 2.89 g/I and 3.3 g/l respectively. The carotenoids recovery yields obtained indicated the applicability of vegetable oils as bio-solvents, providing alternative for petroleum-derived solvents for extraction of carotenoids from Paracoccus bogoriensis. The observed growth indicated a good possibility of amaranth grain and sorghum application as inexpensive medium for carotenoids production by Paracoccus bogoriensis. Although biomass yield by Paracoccus bogoriensis decreased with increase in volume of cultivation, the results obtained showed possibility of semi-industrial production of carotenoids by Paracoccus bogoriensis.