Izvorni znanstveni članak

Biological Decomposition of Phenol by Mixed and Pure Cultures of Algae

Živanka Maloseja ; Hrvatska
Zlatko Pavletić ; Hrvatska

Sažetak

The tests on decomposition of phenol by means of Algae have shown that mixed cultures are considerably more resistant against phenol than pure cultures of tested Algae. Mixed cultures, with the presence of bacteria, decompose phenol much better in a 1000 mg/1 concentration, while pure cultures in most cases perish it a concentration of 1500 mg/1. In general, mixed cultures of benthos Algae from cooling water decompose phenol to about 30% and more in the course of 14 days.
Under pure cultures, at the phenol concentration of 15, 75 and 150 mg/1 changes could not be measured for each species separately, but a rapid growth of the biotic mass of cultivated Algae in test tubes was noticed.
At phenol concentrations of 500 mg/1, the growth of the biotic mass stagnates, whereas at 1000 mg/1 some Algae — the representatives of the genus Pediastrum, Cosmarium and Scenedesmus — perish and the remaining start to lose pigment, which they lose totally at the concentration of 1500 mg/1 at which most of then perish. Of the Algae tested at such a high concentration, only a few representatives of the genus of blue- -green Algae — Chroococcus, Nostoc and Anabaena —• have survived.
It has been observed that at low phenol concentrations the base becomes alkalized (7, 9 — 8, 4), whereas this has not been noticed at higher concentrations.
It is also apparent, that far more time is required for decomposition of phenol by pure cultures. Incubated phenol in a 1000 mg/1 concentration, under room temperature conditions, showed measurable quantities of decomposition after 30 days only. Not all the tested Algae behave equally. The unicellular forms decompose somewath better than the multicellular ones, and the Algae tested show that those belonging to the blue-green Algae variety are the most resistent againtst phenol.
On the basis of the examinations made, we may draw the following conclusions:
Algae can participate in processes of biological decomposition of phenol, but only at certain concentrations.
At lower concentrations, phenol can act stimulatively upon the growth of Algae at slightly higher concentrations of approximately 500 mg/1 they can adapt themselves, whilst at concentrations of 1000 mg/1 many of them can decompose phenol. The highest concentrations of 1500 mg/1 are in most cases lethal to the Algae.
Mixed cultures of Algae from the cooling plant of OKI in Zagreb, in the presence of bacteria, can decompose phenol more efficiently than certain cultivated Algae. Likewise, mixed cultures of Algae are more resistant against phenol than pure cultures.
Under pure cultures the majority of Algae tested decompose phenol at the concentration of 1000 mg/1 at room temperature within 30 days. As a rule, a considerably stronger capability of decomposing is shown by the monocellular Algae, than by the colonial and stringy forms, disregarding their systematic appurtenance. The most intense decomposition was shown by the species Chlorella vulgaris at the utmost resistance against phenol by the blue-green Algae. A concentration of 1000 mg/'l was not decomposed by the phytoplanktonic representatives of the continental stagnant waters: Pediastrum duplex, Cosmarium laeve and Scene- desmus quadricauda.
The species Chroococcus turgidus, Nostoc entophyturn and Anabaena augstumalis were the only one to have survived after 7 days at the highest concentrations of 1500 mg/1.

Ključne riječi

Hrčak ID:

157139

URI

https://hrcak.srce.hr/157139

Datum izdavanja:

31.12.1972.

Podaci na drugim jezicima: hrvatski

Posjeta: 953 *