Research Of Proliferation Conditions By Lactobacillus Fermentation Of Algal Carcass

Dairy has become an important part of people’s daily diet, we usually add lactic acid bacteria in dairy to make the dairy have different biological activities, so lactic acid bacteria and the basis of high quality medium for LAB had become a new research hotspot. The basis medium should be nutrient-rich、extensive、inexpensive、high production rate for cell growth. The algal carcass was the residues after the use of algae to produce biodiesel. It contained large amounts of carbohydrates and protein. Moreover, the residues was generous、extensive、inexpensive. So we choose this cheap and nutritious substances as the substrate of LAB fermentation. Providing nutrient improvement、changing fermentation conditions, as well as appropriate pretreatment to algal carcass to promote the growth of Lactobacillus bulgaricus ATCC 11842 and Lactobacillus Plantarum 09004.First of all, we analysed the nutritional component of algal carcass. The content of protein was measured by Kjeldahl method and the content was 15.32%±0.22%; fat content was 36.6%±0.51% which was measured by Soxhlet. The algal carcass contained 0.27%±0.04% of trehalose、0.08%±0.01% of glucose、0.06%±0.007% of galactose、0.0085%±0.0007% of arabinose. The total amino acid content was 12.26% which was analysed by amino acid analyzer, and the starch content was 17.17%±0.05% which was measured by direct titration method.Lactobacillus bulgaricus ATCC 11842 can grow up to 2.86×107CFU/m L in MRS under 37℃ and grow up to 1.60×107CFU/m L in 2%(w/v)algal carcass medium(ACM). Algal carcass medium was nutritionally enhanced, while added vitamins(include VB2、VB3、VB6、VB9、VB12), amion acids(include cystine、glutamic acid、isoleucine、leucine、typtophan), glucose(the addition amount was 1%, 2% and 5%), peptone(the addition amount was 0.25%,0.5% and 1%). The results showed that by compared the growth curve、production of lactic acid and transformation of p H : Vitamins and amino acids can significantly promote the proliferation of Lactobacillus bulgaricus ATCC 11842(p<0.05)and increased the production of lactic acid significantly(p<0.05); bacterial counts in ACM added 1%(w/v)and 2%(w/v)glucose was significantly higher than added 4%(w/v), and the production of lactic acid was highest in ACM added 2%(w/v), therefore choose the add amount of 2%(w/v) to compound with peptone; bacterial counts in ACM added 0.5%(w/v)peptone was significantly higher than added 0.25%(w/v) and 1%(w/v), and the production of lactic acid in ACM added 1%(w/v) and 0.5%(w/v) was significantly higher than in ACM added 0.25%(w/v); Then research the effect of added peptone and glucose on proliferation, the result showed that: 2%(w/v)glucose compound with 1%(w/v)peptone can significantly promote the proliferation of Lactobacillus bulgaricus ATCC 11842(p<0.05).Research of fermentation temperature and fermentation acidity on the impact of Lactobacillus bulgaricus ATCC 11842, results showed that Lactobacillus bulgaricus ATCC 11842 growed well under 37 and ℃ p H=6.5. The algal carcass was hydrolyzed by 85% metaphosphoric acid, alpha amylase, synergy of 85% metaphosphoric acid and alpha amylase, then fermented with Lactobacillus bulgaricus ATCC 11842. The results showed that Lactobacillus bulgaricus ATCC 11842 could grow well when the algal carcass was pretreatment by synergy of 85% metaphosphoric acid and alpha amylase.Lactobacillus plantarum 09004 can grow up to 2.56×109CFU/m L in MRS under 37℃ and grow up to 1.08×108CFU/m L in 2%(w/v)algal carcass medium(ACM). Algal carcass medium was nutritionally enhanced, while add vitamins(include VB2、VB3、VB6、VB9、VB12), amion acids(include cystine、glutamic acid、isoleucine、leucine、typtophan), glucose(the addition amount was 1%, 2% and 5%), peptone(the addition amount was 0.25%,0.5% and 1%). The results showed that by compared the growth curve、production of lactic acid and transformation of p H : Vitamins and amino acids can significantly promote the proliferation of Lactobacillus plantarum 09004(p<0.05)and increased the production of lactic acid significantly(p<0.05); bacterial counts in ACM added 2%(w/v)glucose was significantly higher than added 1%(w/v)and 4%(w/v), and the production of lactic acid was no significant, therefore choose the add amount of 2%(w/v) to compound with peptone; bacterial counts and production of lactic acid in ACM added 0.5%(w/v)peptone was significantly higher than added 0.25%(w/v) and 1%(w/v); Then research the effect of added peptone and glucose on proliferation, the result showed that: 2%(w/v)glucose compound with 1%(w/v)peptone can significantly promote the proliferation of Lactobacillus plantarum 09004(p<0.05).Research of fermentation temperature and fermentation acidity on the impact of Lactobacillus plamtarum 09004, results showed that Lactobacillus plantarum 09004 growed well under 37 ℃and p H=6.5. The algal carcass was hydrolyzed by 85% metaphosphoric acid, alpha amylase, synergy of 85% metaphosphoric acid and alpha amylase, then fermented with Lactobacillus plantarum 09004. The results showed that Lactobacillus plantarum 09004 could grow well when the algal carcass was pretreatment by synergy of 85% metaphosphoric acid and alpha amylase.The studies showed that the cell counts of Lactobacillus plantarum 09004 and Lactobacillus bulgaricus ATCC 11842 can be maximized when the ACM was added 1%(w/v)peptone and 2%(w/v)glucose. The maximized cell amount of Lactobacillus bulgaricus ATCC 11842 was 2.45×107CFU/m L, while 8.00×108CFU/m L of Lactobacillus plantarum 09004.