Tukey’s estimates of least significant differences were
calculated from the anova analysis. Pearson’s correlation coefficients between all pairs of variables were calculated. During the period of 0–9 days, the highest growth rate of the co-culture (A. niger–B. cepacia) was observed on the third day of postinoculation, after which it plateaued. Biomass of the co-culture was on average 2.1 times higher (P < 0.05) than that of the fungus and 6.9 times higher than that of the bacterium (Fig. 1a). In single cultures, A. niger growth was faster than B. cepacia. While the mycelial mass increased 2.2 times on sixth or ninth day in comparison with the third day, the bacterial mass increased only 1.3 and 1.8 times, respectively. The levels of solubilized phosphate ranged from 0.65 to 1.10 mg mL−1. On the third day, solubilized phosphate showed an increase in 15 times in the B. cepacia culture, 27 times see more Fulvestrant supplier in the A. niger culture, and 23 times in the co-culture in relation to time zero (Fig. 1b). During the subsequent incubation periods, little increases in the amount of solubilized phosphate were observed. The averages observed at the end of the incubation period were 0.57 mg mL−1 for the bacteria, 0.74 mg mL−1 for the fungus, and 0.76 mg mL−1 for the co-culture (Fig. 1b). The efficiency of solubilization of CaP continually increased, and at the end of the incubation period, 100% of the
phosphate was solubilized by co-culture, while single cultures, rates of 78% with B. cepacia and 91% with A. niger were
obtained (Table 1). A similar trend was observed with the production of acid that increased considerably on the third day of incubation (Fig. 2a). This increase was maintained at sixth day in the fungal culture, and subsequently decreased. On the third day, acid produced by the co-culture (5.40 mg mL−1) was significantly greater (P < 0.05) than other cultures and the sum of acid produced individually by the fungal (4.35 mg mL−1) and bacterial (0.55 mg mL−1) cultures. The initial pH of the culture medium was 6.9 (time zero) and decreased on third day to 3.4 in the fungal culture, GBA3 3.7 in the co-culture, and 5.0 in the bacterial culture (Fig. 2b). pH decrease was also observed at the subsequent time points; however, decreases were not as great. On ninth day, the pH values were 3.0 (A. niger), 4.2 (B. cepacia), and 3.1 (A. niger–B. cepacia). No significant difference of the pH was found between fungal and co-culture (Fig. 2b). Glucose content was dramatically reduced even after 3 days of incubation; 68, 99, and 98% reduction in glucose levels were observed in media inoculated with fungi, bacteria, and the co-culture, respectively (Fig. 3a). On the ninth day of postinoculation, glucose content was almost completely consumed in all cultures. Acid phosphatase activity ranged from 9.35 to 52.26 μg pNP h−1 mg−1 dry biomass (Fig. 3b).