Poly-gamma-glutamic acid (γ-PGA) is a new type of environmental friendly polymer material. It has good water absorption
super adsorption and biodegradability
and has great potential for water saving. In this paper
the effects of different γ-PGA application rates (0
1%
3%
5%) on soil water infiltration and soil water and salt transport were studied through indoor soil column simulation experiments. The results showed that with the increase of γ-PGA application rates
both the infiltration capacity and the wetting front movement velocity of soil decreased
and the stable infiltration rate also decreased significantly. Compared with the control
the cumulative infiltrations with 1%
3% and 5% γ-PGA applied decreased by 16.22%
40.34% and 54.72% respectively. The advancing distances of wetting fronts decreased by 17.74%
52.32% and 61.61% respectively. The simulation results of two kinds of infiltration model parameters showed that the absorption rate (S) in Philip formula decreased from 1.669 to 0.854 when the amount of γ-PGA was increased. The empirical coefficient (K) in the Kostiakov formula reduced from 0.855 to 0.792. The empirical index (β) increased from 0.356 to 0.480
and there was a linear negative correlation between the amount of γ-PGA application and the parameters of S and K. The slopes were -16.583 and -1.195 respectively. The application of γ-PGA changed the water and salt distribution in soil profile.With the increase of γ-PGA application
the water content of surface soil (0-10 cm soil layer) increased
while that of deep soil (below 10cm soil layer) decreased
but the change trend of the salinity in soil profile was opposite to that of soil water. This indicated that γ-PGA could reduce the infiltration of soil water and significantly increase the water holding capacity of soil. At the same time
γ-PGA could significantly improve the salt leaching in the soil surface. This study provides a theoretical basis for the use of γ-PGA in water saving and removal of soil salt as a soil amendment.
关键词
Keywords
references
Shih I L,Van Y T. The production of poly (
γ
-glutamic acid) from microorganisms and its various applications[J]. Bioresource Technology, 2001, 79(3):207-225.
Buescher M,Margaritis A. Microbial biosynthesis of polyglutamic acid biopolymer and application in the biopharmaceutical, biomedical and food industries[J]. Critical Reviews in Biotechnology, 2007, 27(1):1-19.
Bajaj I, Singhal R. Poly (glutamic acid):An emerging biopolymer of commercial interest[J]. Bioresource Technology, 2011, 102(10):5551-5561.
Lim S M, Kim J, Shim J Y, et al. Effect of poly-
γ
-glutamic acids (PGA) on oil uptake and sensory quality indoughnuts[J]. Food Science and Biotechnology, 2012, 21(1):247-252.
钟文艺,王家文.
γ
-聚谷氨酸材料固相法合成及研究[J].四川建材,2016,42(6):81-83.
De Cesaro A, De Silva S B, De Silva V A, et al. Physico-chemical and rheological characterization of poly-gamma-glutamic acid produced by a new strain of Bacillussubtilis[J]. European Polymer Journal, 2014, 57:91-98.
Shyu Y S, Hwang J Y, Hsu C K. Improving the rheologicaland thermal properties of wheat dough by the addition of
γ
-polyglutamic acid[J]. LWT-Food Science and Technology,2008, 41(6):982-987.
Yao J, Xu H, Wang J, et al. Removal of Cr(Ⅲ),Ni(Ⅱ) and Cu(Ⅱ) by poly(gamma-glutamic acid) fromBacillus subtilis NX-2[J]. Journal of Biomaterials Science Polymer Edition, 2007, 18(2):193-204.
Stephen I B, Chen B H. Dye adsorption characteristics ofmagnetite nanoparticles coated with a biopolymer poly (