| The effect of L-carnitine on population growth,biochemical composition,yield,fatty acid composition and the metabolism enzyme activity of main fatty acid of heterotrophic Chlorella(Chlorella vulgaris)was studied.The purpose is to improve the nutritional value of heterotrophic Chlorella itself,to reduce the cost of doing business,and to provide scientific basis and data support for its production application,product research and development.The heterotrophic chlorella was strengthened by using L-carnitine at different concentration(0,50,100,200 mg/L)in different time(6h,24 h,96 h),with BG-11 as culture medium,the initial density of 5×10~6 cells/mL,25?,continuous aeration,cultivating time of 144 h,treated with three repeat,each with 3 times.Results:1?L-carnitine has a significant effect on the growth of heterotrophic chlorella population(P<0.05)In 6 h,by adding different concentration of L-carnitine(0 mg/L,50 mg/L,100mg/L,200 mg/L),the heterotrophic chlorella was improved.The population density of treatment group were significantly higher than that of control group(P<0.05),and difference between each treatment group were significant(P<0.05).The population density were in turn 100 mg/L group>200 mg/L group>50 mg/L group>control group.The 100 mg/L treatment group had the maximum population density in 72 h with24.78×10~6 cells/mL,which was 4.96 times that of the initial concentration.In 24 h,by adding different concentration of L-carnitine(0 mg/L,50 mg/L,100mg/L,200 mg/L),the heterotrophic chlorella was improved.In 24-48 h,the population density of treatment group were significantly higher than that of the control group(P<0.05).In 48-144 h,the population density of treatment group were significantly higher than that of control group(P<0.05),and 100 mg/L carnitine treatment group of chlorella population density is significantly higher than the control group and the other two groups(P<0.05).The population density reached the highest in heterotrophic72 h with 30.83×10~6 cells/mL,which is 6.17 times that of the initial concentration.In 96 h,by adding different concentration of L-carnitine(0 mg/L,50 mg/L,100mg/L,200 mg/L),the heterotrophic chlorella was improved.In 96-120 h,the population density of treatment group in the late growth increased,and population density of chlorella carnitine in treatment group were significantly higher than that of control group(P<0.05).There were significant differences in the population density between the three treatment groups(P<0.05).The population density were in turn 100 mg/L group>200 mg/L group>50 mg/L group>control group.The 100 mg/L treatment group had the maximum population density in 120 h with 17.72×10~6 cells/mL,which was 3.54 times that of the initial concentration.After the growth cycle,the dry weight and fresh weight of treatment group were significantly higher than that of the control group(P<0.05),and the difference between each treatment group was significant(P<0.05).The order of chlorella yield in each treatment group was 100 mg/L group>200 mg/L group>50 mg/L group>the control group.The maximum chlorella yield was in 100 mg/L carnitine treatment group in 24 h with dry weight of 1.47 g and fresh weight of 5.78 g respectively.The total lipid and soluble protein content of carnitine addition treatment group in 6 h,24h and 96 h were significantly higher than that of control group(P<0.05),and the difference between each treatment group were significant(P<0.05).The 100 mg/L carnitine treatment group is significantly higher than that of the control group and other treatment groups(P<0.05).The total lipid and soluble protein content of carnitine addition treatment group in heterotrophic 24 h was the highest with 21.79%and 50.81 mg/kg respectively.2?L-carnitine has a significant effect on the fatty acid composition of heterotrophic chlorella(P<0.05)The heterotrophic improvement of chlorella by adding L-carnitine(50 mg/L,100mg/L,200 mg/L)in 6 h showed that:?SFA of 200 mg/L treatment group is significantly lower than control group(P<0.05),and the?SFA of 50 mg/L,100 mg/L treatment group is significantly higher than that of control group(P<0.05).The content of each treatment group was significantly higher than that of the control group(P<0.05),and the difference between the three treatment groups was significant(P<0.05).The ratio of n-3/n-6 in the treatment group of 100 mg/L and 200 mg/L was significantly higher than that in the control group(P<0.05),and the ratio of n-3/n-6 in the treatment group of 50 mg/L was no different from that in the control group.The heterotrophic strengthen of chlorella by adding L-carnitine(50 mg/L,100mg/L,200 mg/L)in the 24 h showed:the?SFA of treatment group was significantly lower than control group(P<0.05),and a significant difference was found in three treatment groups(P<0.05);The contents of the 50 mg/L carnitine group and 100 mg/L carnitine group were significantly higher than that in the control group and 200 mg/L carnitine group(P<0.05),and the difference between the two groups was not significant.The content of the?HUFA group of 200 mg/L carnitine group was significantly higher than that in the control group(P<0.05).50 mg/L carnitine group of?PUFA content is significantly higher than other three groups(P<0.05),and 100mg/L carnitine group and 200 mg/L carnitine group?PUFA content was significantly higher than control group(P<0.05),and there was no significant difference between the two groups.The ratio of fatty acid n-3/n-6 in each treatment group was significantly higher than that in the control group(P<0.05),and the difference between the three treatment groups was significant(P<0.05).The heterotrophic improvement of chlorella by adding L-carnitine(50 mg/L,100mg/L,200 mg/L)in 96 h showed that:the?SFA of the treatment group was significantly lower than control group(P<0.05),and the difference between the three treatment groups was not significant;The content of the 50 mg/L carnitine group was significantly higher than that of the control group and the 100 mg/L carnitine group(P<0.05),but the difference was not significant.The ratio of fatty acid n-3/n-6 in each treatment group was significantly higher than that in the control group(P<0.05),and the difference between the three treatment groups was significant(P<0.05).3?L-carnitine had a significant effect on the metabolic enzymes of the related fatty acids(P<0.05)The heterotrophic improvement of chlorella by adding L-carnitine in 6 h showed that:at the time of 12 h,50 mg/L carnitine group ACC,KAS,FAD2 activity were significantly higher than other three groups(P<0.05),50 mg/L and 100 mg/L carnitine group MAT enzyme activity were significantly higher than the control group and 200mg/L carnitine group(P<0.05),and there was no significant difference between the two groups.At 36 h,the activity of ACC,MAT and FAD2 enzyme in each treatment group was significantly different(P<0.05),and the activity of the enzyme above 50mg/L carnitine group was the highest.The activity of KAS in the 50 mg/L carnitine group was significantly higher than that in the other 3 groups(P<0.05),and the 100mg/L and 200 mg/L carnitine group was significantly higher than the control group(P<0.05),but the difference between the two groups was not significant.At 108 h,100mg/L and 200 mg/L carnitine group more than four kinds of enzyme activity were significantly higher than the control group,and 50 mg/L carnitine group(P<0.05),and no significant difference between the two groups,50 mg/L carnitine group was significantly higher than control group(P<0.05).The heterotrophic improvement of chlorella by adding L-carnitine in 24 h showed that:before add L-carnitine to strengthen,the above four kinds of enzyme activity content difference was not significant,at 36 h,between different treatment group ACC,MAT and FAD2 enzyme activity were significant difference(P<0.05),and 100 mg/L carnitine group ACC and MAT the highest activity.100 mg/L carnitine group KAS enzyme activity was significantly higher than other three groups(P<0.05),50 mg/L,200 mg/L carnitine group KAS activity is significantly higher than the control group(P<0.05),but there was no significant difference between the two groups.At 108 h,there were significant differences in the activity of 4 enzymes between the treatment groups(P<0.05).The heterotrophic improvement of chlorella by adding L-carnitine in 96 h showed that:before add L-carnitine to strengthen,the above four kinds of enzyme activity content difference was not significant,at 108 h,the treatment group of ACC,KAS and FAD2 enzyme activity were significant difference(P<0.05),and the enzyme activity of 50 mg/L carnitine group was the highest.The MAT enzyme activity of 50mg/L carnitine group was significantly higher than that in the other 3 groups(P<0.05),and the carnitine group of 100 mg/L and 200 mg/L was significantly higher than that in the control group(P<0.05),and the difference between the two groups was not significant.Conclusion:Under the condition of this experiment,24 h in chlorella heterotrophic culture,add 100 mg/L carnitine can increase through acetyl-coa carboxylase,propylene acyl-CoA:turn ACP acyl enzyme,beta-ketone fatty acyl-ACP synthase,?12 fatty acids to saturated enzyme activity,to improve the composition of fatty acids,especially polyunsaturated fatty acid and n-3/n-6 fatty acid ratio increases,thus promote the population growth and improve its biochemical composition. |
PDF Full Text Request