Optimization Of Production Process Of Plant Lactobacillus To Produce Astaxanthin In 5L Ferme Nter

Natural astaxanthin as a powerful antioxidant,its unique conjugated diene and chemical structure of unsaturated carbonyl gives it a s trong antioxidant activity,it also has anti-cancer properties,enhancement immunity,prevention of cardiovascular disease,diabetes and other functional properties,it has a broad market prospects for being widely used in food,cosmetics,pharmaceuticals,fodder and other industrial fields,however China’s astaxanthin industry was still in the initial stage,the production of bacteria was haematococcus pluvialis and phaffiarhodozyma whichhad used abroad for many years,due to the high cost of production and technology,the production of natural astaxanthin was limited resulted in its price of international market being high and restricting the application of natural astaxanthin to a certain degree.This paper used a plant lactobacillus with excellent produc tion performance in the cultivation conditions and the extraction process of astaxanthin which was not only characterized by the high content of astaxanthin from haematococcus pluvialis,but also easy to cultivate from the character of phaffia rhodozyma,molasses were used as the main raw material,the yield of Lactobacillus and the yield of astaxanthin were improved by optimized by seed culture medium,optimization of fermentation conditions in order to reach high-density fermentation.The main results were follows:The molasses were used as carbon source to optimize the culture medium,and the effects of initial carbon source concentration on the growth of Lactobacillus and the accumulation of astaxanthin were investigated.The results showed the initial carbon source concentration of 20 g/L was more suitable for Lactobacillus fermentation on the seed shake flask culture and 5L fermentor culture,the best seed culture formula was determined as follows:molasses 20.0g/L（based on total sugar content）,（NH₄）₂SO₄ 2.0 g/L,Na₂HPO₄·12H₂O 1.0g/L.The fermentation conditions of Lactobacillus 5L reactor were studied.It was found that the above-mentioned culture medium was used to cultivate Lactobacillus,and seed inoculation age was not obvious effect on the final biomass and astaxanthin production,but the growth rate of 16 h inoculation age was the highest,which could significantly shorten the fermentation cycle;high p H（<4.0）value was not conducive to the proliferation of plant lactobacillus and astaxanthin accumulation,soplant lactobacillus fermentation process should be constant control of the pH 5.0;higher dissolved oxygen could promote the growth and accumulation of Lactobacillus astaxanthin,dissolved oxygen fermentation conditions of Lactobacillus should be controlled at 40%⁸0%,in the premise of ensuring adequate oxygen,plant lactobacillus in the stable period could still be a large number of accumulation of astaxanthin.Thefed-batch fermentation with pH-stat,the fed-batch fermentation with the total sugar and fed-batch fermentation with DO-statwere carried out in 5 L reactor while the batch fermentation experiment as a control.The results showed that the biomass of the Lactobacillus and the accumulation of astaxanthin could be improved by the three kinds of feeding methods,but fed-batch fermentation with DO-stat was the best compared with batch fermentation.In this feeding mode fermentation,15¹6h began to feed,through the flow of feed solution to control the dissolved oxygen maintained at 40%to 80%while kep t the stirring speed and ventilation volume unchanged,feed fluid for 35 h,feeding concentration was molasses200 g/L（based on total sugar content）,（N H₄）₂SO₄20.0 g/L,Na₂HPO₄·12H₂O 10.0g/L,the amount of feed material accounted for total loading volume20%and each liter consumped the total sugar concentration of70 gof molasses（based on total sugar content）,（NH₄）₂SO₄7.0 g/L,Na₂HPO₄·12H₂O3.5 g/L at the end of the fermentation,the highest biomass of Lactobacillus reached 39.73 g/L,astaxanthin yield was1.88 g/L,which was higher than that of batch fermentation 2.6 times and astaxanthin accumulation increased by 2.8 times,the result of sugar concentration analysis of three modes fed-batch fermentation showed that the low and enough sugar concentration was beneficial for Lactobacillus growth and the accumulation of astaxanthin in the fermentation process.