China Animal Husbandry and Veterinary Medicine ›› 2023, Vol. 50 ›› Issue (9): 3562-3572.doi: 10.16431/j.cnki.1671-7236.2023.09.012

• Nutrition and Feed • Previous Articles     Next Articles

Process Optimization and Structure Analysis of Calcium Oxide and Sodium Carbonate Pretreatment of Reed Straw

SUN Zhuwen1,2,3,4, LIU Zhengqun2,3,4, ZHU Longbo1,2,3,4, LI Ning2,3,4, LIU Yanrong1,2,3,4, LIANG Shiyue2,3,4, ZHENG Zi2,3,4, MU Shuqin2,3,4, YAN Jun2,3,4, SUN Chao1   

  1. 1. College of Animal Science and Technology, Northwest A&F University, Yangling 712100, China;
    2. Institute of Animal Science and Veterinary, Tianjin Academy of Agricultural Sciences, Tianjin 300381, China;
    3. Tianjin Key Laboratory of Animal Molecular Breeding and Biotechnology, Tianjin 300381, China;
    4. Tianjin Engineering Research Center of Animal Healthy Farming, Tianjin 300381, China
  • Received:2023-02-06 Online:2023-09-05 Published:2023-08-24

Abstract: 【Objective】 The experiment aimed to investigate the optimal process conditions for lignin degradation of reed straw at the dead leaf stage by combined pretreatment with calcium oxide (CaO) and sodium carbonate (Na2CO3) and its structural changes.【Method】 The experiment was conducted to investigate the removal of lignin and hemicellulose by selecting four factors:Treatment time,treatment temperature,feed-to-liquid ratio,and CaO addition on the basis of 2% Na2CO3 addition in a gradient test.The Box-Behnken response surface optimization test was conducted to investigate the optimal pretreatment process for lignin degradation based on the results. Subsequently,the structural changes of reed under the optimal treatment conditions were analyzed by scanning electron microscopy (SEM),Fourier infrared spectroscopy (FTIR),and X-ray diffraction (XRD).【Result】 The lignin and hemicellulose removal rates of reed straw differed significantly (P<0.05) at different treatment times,treatment temperatures and CaO additions,and there were no significant differences at different feed-to-liquid ratios (P>0.05).The response results showed that the regression model was extremely significant (P<0.01),and all three factors had extremely significant effects on lignin removal rate (P<0.01),and the magnitude of the effects of the three factors on lignin removal rate were treatment temperature,CaO addition,and treatment time in order.The optimal pretreatment process conditions were 8.44% CaO addition,5.52 h treatment time,and 49.58 ℃ treatment temperature when Na2CO3 addition was 2% and material-to-liquid ratio was 1∶3.Under this pretreatment condition,the lignin removal rate of reed straw reached 23.75%,which was close to the model predicted value (24.97%). After optimization, SEM results showed that the surface of reed straw was broken and the pores were enlarged and increased;FTIR results showed that the absorption peak intensities of hemicellulose and lignin corresponding to chemical bonds of reed straw were reduced;XRD results showed that the relative crystallinity index (CrI) of cellulose of reed straw changed from 37.21% to 46.66%.【Conclusion】 The process conditions of combined pretreatment of reed straw with CaO and Na2CO3 by response surface methodology were reasonable and feasible.The surface morphological structure,chemical structure of lignocellulose and cellulose crystalline structure of the pretreated reed straw were significantly changed. The results could provide technical support for the high-value development and utilization of non-conventional feed resources.

Key words: reed straw; pretreatment; response surface optimization; lignin removal rate; structure analysis

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