Study On The Extraction Of L-arginine From Rabbit Hair

The rabbit hair resources are seriously wasted in China,such as a large number of rabbit hair byproduct,short rabbit hair,oarse hair and heterotypical fibre not suitable for spinning in the textile industry.This rabbit hair waste belongs in the animal keratin fiber,which containing abundant keratin.According to statistiscs,there are dozens of tons of wool waste have been discarded in landfill in China every year.It is a waste of valuable resources of keratin,and increase the environmental pollution.If we can recycle the waste of rabbit hair,not only reduce the pollution result from accumulation of rabbit waste,but also makes the waste resources regain the use value.In recent years,there is much about the research on the comprehensive utilization of animal keratin fiber,also has obtained some achievements.The compositions and content of amino acids of rabbiat hair were analyzed via automatic amino acid analyzer in the article,and it found rabbit hair is considered to be good material,which L-arg of content at about 6.32%,higher than that other raw material prepared the L-arg.This article presented rabbit hair as raw material and extracted L-arg from rabbit hair.Then the continuous and operational process was determineds by optimizing the process cinditions,to achieve the entire production process of industrial inputs.First,we explored the dissolution of rabbit hair by acid hydrolysis method,and optimized the process according to rabbit hair dissolution rate and the concentration of L-arg.Hydrochloric acid quantity,reaction temperature and time were examined by orthogonal test,and the best hydrolysis process of rabbit hair was optimized to be as the reaction temperature was 115?,the reaction time was 8h and the bath ratio of rabbit hair and 8 mol/L hydrochloric acid is 1:2.Under the optimum condition,the dissolving rate of rabbit hair was 98.38%,and the concentration of L-arg was 41.46g/L.Secondly,the rabbit hair hydrolysate was studied on decolorization and desalination.Compared the various processing methods,two-step method was suggested to decolor and desalt the rabbit hair hydrolysate.Most of acidic amino,neutral amino and part of inorganic salts were remove by the following concentration and crystallization,the loss rate of salts and L-arg were 18.7%and 5.2%respectively in the process;Then rabbit hair hydrolysate was adsorbed on resin.The adsorption performance for pigment,inorganic salt and L-arg of four selected resin were measured according to reaction temperature,resin usage and time,the determined the final process plan is that the rabbit hair hydrolysate was adsorbed successively through D3520 resin and 201×x7 resin.The best procssing plan optimized to be as follows:the reaction temperture was 30? or indoor temperature,the reaction time was 1?2h,and the bath ratio of resin usage and rabbit hair hydrolysate is 1:3.Under the optimum condition,the decolourization ratio was 88.53%,desalting rate was 52.17%and loss rate of L-arg was 15.83%.Third,the influences of time,pH,and the initial concentration of L-arg and adsorption isotherm on 001x7 resin,D001 resin and D155 resin were measured,the results showed that the equilibrium time of these three ion exchangers were 60min,60min,and 150min respectively;the best pH value of 001×7 resin and D001 resin was between 6?7,and best pH value of D155 resin was 8.The best initial concentration also were 20g/L.And the maximal equilibrium adsorbances were 66.67mg/g,70.42mg/g,and 46.51mg/g,which the adsorption behavior of these three resins can be well described by Langmuir equation.Then,the breakthrough curves of adsorption for L-arg of three resin at different flow velocity by dynamic method were measured,the results showed that low velocity made for the adsorption of L-arg and best flow velocity of L-arg solution was lml/min.Considering all of the above conditions,001x7 resin was chose as the ion exchanger of technology of sparating L-arg from the rabbit hair hydrolysate.And we computed the integral for the breakthrough curves of 001 x7 resin at lml/min,and found the bath ratio of resin usage and rabbit hair hydrolysate is 1:4.Next,ammonium hydroxide was chose as the eluting agent.The elution curves were investigated in the different concentration of ammonium hydroxide and flow velocity,and the results showed that the best concentration of eluting agent was 2mol/L,and best flow velocity was lml/min.Under the optimum condition,the adsorption quantity was 64.06mg/g,and elution rate reached 92%.Finally,Using the completed process after optimized conditions,eventually formed a entire continuous process to extract L-arg,which suitable for industrial production and percentage extraction of L-arg were 3.15%and 49.85%respectively.