Growth and phenol activity of Pseudomonas aeruginosa strain 101/1 in batch cultures.

Strain 101/1, isolated from petroleum wastewater sediment was classified as Pseudomonas aeruginosa. In wild type condition the strain tolerated phenol in concentration 1,000 mg/L under aerobic conditions and 800 mg/L under denitrifying conditions. As a result of adaptation to phenol the resistance of the strain to the compound increased to 1,600 and 1,400 mg/L, respectively. Maximum phenol activity under aerobic and denitrifying conditions was 350 and 65 mg/L x day-1, respectively. Under denitrifying conditions a reduction in incubation temperature from 30 degrees C to 20 degrees C resulted in two-fold drop in phenol activity of the adapted strain and reduction in tolerance to phenol by 400 mg/L.

Phenol-degrading denitrifying bacteria in wastewater sediments.

An attempt was made to isolate denitrifying bacteria capable of degrading phenol from anoxic wastewater sediments and compost (vegetable soil). The greatest phenol-degrading activity was shown by autochthonous microflora from petroleum wastewater sediments (PWS) and by denitrifying microflora from nitrogenous wastewater reservoir sediment (NWRS). Eight strains of denitrifying bacteria able to degrade phenolic compounds were isolated, six of which were from the petroleum wastewater sediments. The highest activity of phenol degradation (23.5 and 23 mg/L/day) in denitrifying conditions was shown by strains 54/1 and 83/2, both from petroleum wastewater sediments, which were classified as Pseudomonas aeruginosa and Alcaligenes faecalis, respectively.

Microbial degradation of phenol in denitrifying conditions.

The biodegradation of phenpol in anaerobic conditions by mixed population of bacteria in batch cultures or continuous cultures in packed bed reactor in medium with phenol as sole carbon source was effective. Phenol in concentrations up to 500 mg/l was degraded by bacteria in batch cultures (incubation temperature 30 degrees C) with increasing maximal rate without lag phase and at higher concentrations (up to 1000 mg/l) the activity of the bacteria was preceded by a lag phase lasting from 9 to 15 days. Phenol was degraded in continuous cultures with maximum efficiency (about 2500 mg/l x day) in the following conditions: incubation temperature 30 degrees C, phenol concentration in the medium of 200 mg/l and retention time of about 2 hours. Lowering of the temperature of the culture to 13 degrees C and 20 degrees C resulted in 10 and 5-fold decrease in the efficiency of the process, expressed as mg/l X day, respectively. Analysis of the composition of the bacteria among the facultatively growing Gram-negative rods showed that the incubation temperature visibly affected the species composition and domination pattern of denitrifying bacteria although their percent participation remained the same.

Bacterial microflora in Stichococcus bacillaris culture in nitrogenous-organic wastewaters.

The quantitative and qualitative composition of the population of heterotrophic bacteria accompanying Stichococcus bacillaris in culture in non-sterile nitrogenous-organic wastewater was examined. During 5 days of incubation the total number of bacteria did not show any marked changes and averaged 4 X 10(6) cells per ml. Twenty per cent of the isolated bacterial strains were gram-positive. Gram-negative rods were dominated by Enterobacteriaceae (40%) and Pseudomonas (17%).

Bacterial microflora of nitrogen industry wastewaters.

The quantitative and qualitative composition of heterotrophic bacteria found in two types of wastewaters from the nitrogen industry was determined. The number of bacteria in the wastewaters was 10(4) to 10(6) cells/ml. Gram-negative bacteria accounted for 57% of the bacteria in the final retention reservoir whereas their number in the wastewaters discharged into surface waters was 90%. The dominating species among the Gram-negative bacteria was Pseudomonas, irrespective of the composition of the wastes and means by which they were discharged into the Wisla. The studied microflora utilized in different metabolic processes nitrogen compounds present in the wastes.

Heterotrophic bacteria accompanying Stichococcus bacillaris in laboratory cultures.

The number and composition of bacterial microflora accompanying Stichococcus bacillaris in various media with urea was determined. The number of heterotrophic bacteria during 5 days of incubation increased 10-fold. Only some of the isolated bacterial strains were able to grow in medium for algae supplemented with dead S. bacillaris cells. It is suggested that bacteria utilize organic matter released to the medium by S. bacillaris. The most numerous among the isolated bacteria were Enterobacteriaceae. The order of domination by bacterial populations distinguishes nonaxenic cultures of S. bacillaris from cultures of other algae.

Effect of cadmium on the growth of Chlorella vulgaris and Stichococcus bacillaris.

The growth of Chlorella vulgaris and Stichococcus bacillaris cultures in media containing from 20 to 100 mg Cd/l was studied. The examined strains were found to be highly resistant to the action of cadmium since the highest concentration of the metal used limited the production of dry weight (during 5 days of cultivation) by less than 50%. The lower production of chlorophyll a by S. bacillaris cultures in media containing from 60 to 100 mg Cd/l and 2-fold elongation of the cells point to lower tolerance of the strain to cadmium than that shown by C. vulgaris.

Properties ofChlorella vulgaris strain adapted to high concentration of ammonium nitrogen.

Chlorella vulgaris is very sensitive to high concentrations of ammonium nitrogen. In medium containing 0.33 g NH4-N/1 its growth is inhibited by 50%. Prolonged incubation of the strain in media inhibiting any increase in cell number enabled the isolation of a strain with enhanced tolerance to high ammonium nitrogen concentration. The strain has been designated Chlorella vulgaris/AA. The concentration of nitrogen inhibiting the growth of the strain by 50% was 195 g NH4-N/1. The acquired character proved stable. The isolated strain also demonstrated increased tolerance to high concentration of urea nitrogen. Chl. vulgaris/AA cells were larger than the cells of the parental strain.