Chemical composition and molecular weight distribution of dissolved organic matter produced by bacterial degradation of green algae

Abstract

Abstract-Chemical composition and molecular weight of dissolved organic matter were determined by employing chemical analysis and Sephadex Gel filtration method with respect to bacterial degradation products of green algae . The chemical composition is as follows; pigment materials 15%, lipid and organic acid materials 30% , proteinous materials 26% and carbohydrate materials 8%. The molecular weight of the dissolved organic matter is distributed in wide ranges. Organic matter with high molecular weight (> 50,000) consists mainly of proteinous and carbohydrate materials, intermediate one (1,500-50,000) consists of pigment and lipid materials. The composition of lower molecular weight matter is not yet known.The dissolved organic matter produced by bacterial degradation of green algal cells is characterized by yellow colouring, which originates in pigments (in main chlorophyll pigments), and high molecular weight organic substances, which consist almost of prot einous substances with lesser amounts of carbohydrate substances . Although there is a considerable difference between the dissolved organic matter of bacterial degradation products and that in natural water, the former is suggested to be an important source of the latter.

Interactions of ferric and ferrous irons and organic matter in water environment

“…Accordingly, as to the coprecipitation behavior, no significant difference was recog nized between the dissolved organic matter present in natural water and the dissolved organic matter produced by bacterial degradation of green algae, although the chemical composition of dissolved organic matter differed (AKIYAMA, 1972).…”

“…In lake water, formation of iron hydroxide from dissolved ferric and ferrous irons seems to occur in water layers near the bottom, in the interface layers between anaerobic and aerobic layers in the stagnation period and in all layers in seasonal water circulation, as suggested in Lake Haruna (AKIYAMA, .1971). In sea water, the hydroxide of iron is formed near the mouth of a river, where it is pre cipitated rapidly (JOYNER 1964;COONLEY et al 1971) and the formation of hydroxide may occur by microzonal alkalinization proposed by SIEBURTH (1965). In these cases of natural waters, the selective coprecipitation may have effects on the composition of dissolved organic matter and particulate organic matter, and also have resultant effects on the food value of dissolved organic matter in natural water.…”

“…was prepared according to the method described in the previous paper (AKIYAMA, 1972). Sample solution containing dissolved organic matter to less than 5 mgC/1 was used in coprecipitation experiments.…”

“…Dissolved organic matter was fractionated into pigment, lipid, high molecular proteinous and low molecular proteinous and carbohydrate fractions by the same method described in the previous paper (AKIYAMA, 1972).…”

Decomposition characteristics of particulate organic matter in hiroshima bay

“…On the other hand, the fraction of high molecular weight over 100,000, which may be assumed to be the product of bacterial metabolism, was as large as that of fraction 3 at the third day, though it did not exist at all at the beginning. Akiyama(1972) pointed out the existence of three peaks of the molecular weight in the ranges of 0-700, 5,000 -10,000, and 150.,000-200,000 on bacterial degradation products of green algae Changes of molecular weight distribution of DOC in run 6. Fraction 1< 500, 500 < Fraction 2 < 10,000, 10,000 < Fraction 3< 100,000, 100,000<Fraction 4. molecular weight fraction consisted of large amounts of proteinous material and small amounts of carbohydrate, the intermediate fraction was a chlorophyll degradative product, and the low fraction might be free amino acid, organic acid, and free sugars.…”