Polysaccharides in soil

Martin, J. P., Ervin, J. O., and Shepherd, R. A. (1966). Decomposition of the iron, aluminium, zinc and copper salts or complexes of some microbial and plant polysaccharides in soil. Soil Sci. Soc. Am. Proc. 30,196-200. 

Chemical studies have yielded results that are in harmony with the ideas expressed above. These have involved the use of oxidizing agents, chiefly sodium periodate, for the destruction of polysaccharides in soils. In such studies, any decrease in aggregate stability following periodate treatment should be a measure of the contribution of polysaccharides to this stability. From such work Mehta et al. (1960) concluded that polysaccharides are not the sole agents responsible for natural aggregation. Greenland et al. (1962) in similar... 

MARTIN J.P., ERVIN J.O. and SHEPHERD R.A. 1966. Decomposition of Iron, Aluminium, Zinc and Copper Salts or Complexes of some Microbial and Plant Polysaccharides in Soil. Proceedings of the Soil Science Society of America, 30,196-200. 

There are three main lines of evidence to support the involvement of polysaccharide in soil aggregation firstly, the strong adhesive qualities possessed by many polysaccharides secondly, the effect of the addition of polysaccharide to soil particles on the formation of stable synthetic aggregates, and thirdly, the effect of periodate and tetraborate, which remove carbohydrate, in disrupting natural aggregates. 

This chapter has described several of the major functions of polysaccharide in soil, such as the aggregating effect and water retention. Many of these functions are also performed to some extent by other soil components, but an important difference is that polysaccharide can be synthesized by plants and this gives them the ability to modify and improve their environment. In conclusion, the physical state in which plant roots and many microorganisms flourish should be emphasized. Frequently each type of organism has associated with it carbohydrate in the form of a slime or gel which has the effect of increasing contact with soil surfaces. Thus the gel, essentially a body of water, greatly facilitates the movement and uptake of nutrients. 

LASIK Y., GORDIYENKO S.A. and KALAKHOVA L. 1978. (Decomposition of bacterial polysaccharides in soil). Soviet Soil Science translated from Pochvovedenie, 1978, 151-153. 

MARTIN J.P. 1971. Decomposition and binding action of polysaccharides in soil. Soil Biology and Biochemistry, 33-41. 

MEHTA N.C., STREULI H., MULLER M. and DEUEL H. 1960. Role of polysaccharides in soil aggregation. Journal of the Science of Food and Agriculture, 11, 40-47. 

STEVENSON F.J. 1957. Investigation of amino polysaccharides in soil. II. Distribution of hexosamines in some soil profiles. Soil Science, 8 , 99-106. 

The different groups of biomolecules, including fatty acids, triglycerides, polysaccharides, and proteins (illustrated in Figure 4.9) decompose at different rates depending on their composition. Lipids and fats are slower to decompose in soil because of their insolubility in water. Large polysaccharides are also insoluble in water but are more quickly decomposed than fats. Proteins and compounds such as DNA and RNA are more quickly decomposed in part... 

For the reasons stated above, deep intrusion of degrading microbes into polysaccharide-plastic films is demonstrably and theoretically improbable. Since starch removal does occur when the films are buried in soil, the primary mechanism must be microbial production of amylase in or near a pore, diffusion of the enzyme into pores and diffusion of soluble digestion products back to the surface where they are metabolized (Figure 3). This mechanism would be the only choice when the pore diameter is too small to admit a microbial cell (i.e., at diameters < 0.5 /im). An alternative mechanism could be diffusion of a water-soluble polysaccharide to the film surface, at which point degradation would occur. None of the materials used in these investigations showed loss of starch even when soaked in water for extended periods with microbial inhibitors present. Therefore, diffusion of amylase to the substrate rather than diffusion of the substrate to the film surface is the more likely mechanism. 

The scheme proposed above requires microbial colonization of the material and excludes degradation by amylases and cellulases that are present in soils (28), but are not newly synthesized or associated with microbial cells. Active polysaccharide hydrolases are found in nearly all soils, but these enzymes are primarily bound to soil organic matter or mineral components attachment is firm enough to severely limit migration of the enzymes from surrounding soil to the film. 

Bitton, G., Henis, Y. Lahav, N. (1976). Influence of clay minerals, humic acid and bacterial capsular polysaccharide on the survival of Klebsiella aerogenes exposed to drying and heating in soils. Plant and Soil, 45, 65-74. 

Polysaccharides probably constitute one of the most abundant fractions in soil organic matter and they are present as such or combined with the extracted humic fractions. As can be seen from the findings with soil extract and humic fractions (see Section 5.2), water-soluble materials are made up of a complex mixture of polysaccharides, proteins, phenolic and lignin-derived compounds, as well as other aliphatic materials. These compounds... 

Interest in soil saccharides, and especially in soil polysaccharides, is relatively recent, and their studies may be considered to be in the modern era of soil organic matter research. Martin (1945,1946) established that the slimy bacterial products... 

There is a need to resume studies of soil saccharides and peptides. These can compose as much as 30-40% (when account is taken of the compositions of humin materials). Much is known about how polysaccharides of known structures interact with soil colloids, but it has not been possible as yet to know in sufficient detail the structures of the polysaccharides that persist in the soil. Hence we do not know the mechanisms of their binding to soil mineral colloids. The same applies for the peptide materials, though it is clear that polysaccharides and peptides have important roles in soil structure formation and stabilization. 

Geoghegan, M. J., and Brian, R. C. (1946). Influence of bacterial polysaccharides on aggregate formation in soils. Nature (London) 158, 837. 

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