ISSN:
1573-5087
Keywords:
anaerobic methanogenic thermophilic digestion
;
auxin
;
biogas
;
IAA
;
IBA
Source:
Springer Online Journal Archives 1860-2000
Topics:
Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
Notes:
Abstract A large amount of solid waste remains after the production of instant coffee. This waste has to be moved to dumps, where it poses a threat of environmental pollution. Treatment of this waste by anaerobic methanogenic thermophilic digestion produced, besides biogas, a digested slurry which was used as a growth medium for horticulture, and proved to be a suitable and economical substitute for peat moss. Biological tests with mung bean cuttings and Grevillea plantlets showed promotional effects on rooting of the slurry and its sieved fraction extract, washed with water (Capul). Green coffee beans, instant coffee waste, its anaerobically-digested slurry and Capul were extracted by various methods and the extracts were analyzed by TLC, HPLC and GC/MS. Examinations showed clearly the presence of IAA and IBA in free and bound forms in all the substrates. The values of free and bound IAA were calculated by use of an internal standard and GC/MS. The amount of conjugated IAA was found to be much higher than that of free IAA, in both the coffee beans and instant coffee waste (11.1 vs 2.7 nmol g−1, respectively). In the digested slurry and Capul, however, most of the IAA was present as the free form and was approximately 23.5–33.0 nmol g−1, which is almost ten times more than in the waste, and almost twice the total amount of IAA in coffee beans. It is postulated that the high levels of free IAA in the digested instant coffee waste are a result of catabolism of tryptophan by anaerobic bacteria.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00024172
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