| In recent years, side effects of antibiotics have aroused concerns with the improvingtechnology of research. The phenomenon of wide use of antibiotics in the aquaculture industryhas become the key factors which has limited international trade of animal products from China.Probiotics can solve some of the negative problems caused by antibiotics and can achieve safeand green production without pollution and residue. In this study, the probiotics with Bacillussubtilis and Corynebacterium glutamicum were obtained by liquid fermentation and solidfermentation with the strain of JMU315-A and JMU315-B, producing L-tryptophan and peptides.After drying and smashing, the probiotcs were uesed for mixing with animal fed to reduce theproduction cost of L-tryptophan.The results are as follows:1, Optimized individual fermentation process for Bacillus subtilis JMU315-A:18h,37℃and initial pH of7.50for activating the seed,30mL in300mL shakers for the seed medium.37℃, initial pH of7.50,0.5%sucrose,4%soybean residue,0.6%NaCl and48h for liquidfermentation.50%water content,37℃and48h for solid state fermentation. Fermented beancurd was content with some microbial activity, including3740.91U/g*(g*per gram solidfermentation medium) of protease activity,11.3mg/g*of peptide content and1.03×109pfu/g*asthe number of Bacillus subtilis strain.2, Optimized individual fermentation process for Corynebacterium glutamicum JMU315-B:22h,32℃and initial pH of6.80for activating the seed,20mL in500mL shakers for the seedmedium. Glucose as the best carbon source for fermentation. Corn syrup mixed with ammoniumsμLfate in3:2as the nitrogen source for fermentation.8%of inoculation,32℃,6.80of initialpH and96h for fermentation.10g/100mL for initial glucose concentration,1g/100mL for theinitial concentration of ammonium sulfate, every12h fedding glucose and ammonium sulfatefor5times to the final concentration of4g/100mL and4g/100mL respectively. L-tryptophanconcentration producing by the optimal fermentation achieved to340mg/L, L-tryptophan of fedgroup were50%more than those without. L-tryptophan of optimal fermentation was8.6times of before.3, The optimized process for the fermentation with JMU315-A and JMU315-B: JMU315-Awere inoculated24h before JMU315-B. Inocu Lation ratio for JMU315-A and315-B was4:1and the totle inoculation was9%.140g/L of glucose,40g/L of soybean residue for thefermentation. Temperature for fermentation was controlled as that,37℃for first24h,35℃for24-48h,32℃for the time latter.1%of initial ammonium sulfate, with five times of fedding to4%every12h. Take the concentration of soybean residue,the number of ammonium fed andconcentration of glucose as there main factor of orthogonal experiments in four levels. Thefactors checked from the most important for L-tryptophan producing to less were concentrationof soybean residue, concentration of glucose and the number of ammonium fed. With theoptimized fermentation conditions, content of L-tryptophan reached the maximum(961mg/L)at108h of complex fermentation,which was50%more than single fermentation ofCorynebacterium glutamicum in best cultivate conditions.90%humidity,37℃,75%moisturecontent for solid state fermentation process. After48h for solid fermentation,the content ofpeptides and L-tryptophan were12.7mg/g*(per gram of solid medium) and3.23mg/g*respectively. After13h of drying the solid medium at80℃, L-tryptophan content in the mediumwas10.8mg/g**(g**refers to the sample per gramdry matter).4, The probiotics were proved that it can increase feed conversion, non-specific immunityand promote the growth of probiotics in intestinal tract of chicken. It can be checked that5%ofthe preparations is the best formula mixed ration. With the addition, it could keep the aminoacids of feed in balance, increase feed conversion and non-specific immunity markedly. Theprobiotics could meet the need for increasing economic efficiency and improve economicefficiency. In the future study, more economic benefit would be reached by mix the feedfollowing the ratio of crude protein to cellulose. |
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