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Estimation of Bacterial Numbers by Indirect Methods
Published in Maria Csuros, Csaba Csuros, Klara Ver, Microbiological Examination of Water and Wastewater, 2018
Maria Csuros, Csaba Csuros, Klara Ver
The ability of an organism to degrade the amino acid tryptophane can be detected by testing for indole, the product of tryptophanase. Reaction of indole with an aldehyde results in a colored end product. Organisms that produce the enzyme tryptophanase are able to degrade the amino acid tryptophane into pyruvic acid, ammonia, and the product indole. Indole is detected by its combination with the indicator aldehyde (available commercially) to form a colored end product.
Screening, identification and optimization of Bacillus species isolated from textile effluents in malachite green degradation
Published in Bioremediation Journal, 2023
K. B. Roopa, S. Raj Surabhi, B. S. Gowrishankar
Gram’s staining was performed to confirm whether the organisms were Gram positive or Gram-negative bacteria. The results proved that both the organisms were Gram-positive bacilli (Figure 2a and b). Several biochemical tests like motility, Catalase activity, Starch hydrolysis, Indole test, MR-VP tests, Citrate utilization test and Carbohydrate fermentation test were performed to further characterize the organisms. Motility tests justified that both the organisms were motile (Table 2). Catalase activity validated that both the organisms produced catalase enzyme and were aerobic bacteria. Starch hydrolysis test proved that both the organisms were capable of producing amylase enzyme. Indole test showed that the organisms were negative for the production of compound Indole that has formed by the release of tryptophanase enzyme. SITBT1 was negative for acidic end product, but SITBT2 was positive, based on MR reaction. VP test corroborated that both the organisms were negative for the production of alkaline neutral product. Citrate utilization test proved that SITBT1 was positive for the production of citrase enzyme and SITBT2 was negative for the production of the enzyme. Different sugars like Glucose, Sucrose and Lactose were used as sources of carbohydrates in the carbohydrate fermentation test. SITBT1 was capable of utilizing glucose, sucrose and lactose for the fermentation process and proved that SITBT1 was aerobic bacterium. SITBT2 was capable of utilizing only glucose and sucrose but not lactose for their growth and proliferation and proved that it was aerobic bacterium (Table 3). Further, to confirm that the organisms belonged to different species, antibiotic susceptibility test were performed. Several antibiotic disks was used (Table 2) and based on the zone of clearance (MIC) it was confirmed that both the organisms belong to different species.
Exploration on microbial load and nutrient source in coal-bed methane produced water
Published in Energy Sources, Part A: Recovery, Utilization, and Environmental Effects, 2022
Diptangshu Mukherjee, Vetrivel Angu Selvi, Jhuma Ganguly, Reginald Ebhin Masto
The isolation and growth of environmental microbes in a laboratory is very complicated, because mimicking of ecological growth necessities and circumstances in laboratory is difficult (Budwill 2003). The water sample was enriched into a liquid basal medium supplemented with a substrate and as a result culture growth occurred. By using a proper technique, an obligate anaerobic strain was derived and identified. The colonies of the strain were round, have translucent color, were smooth in texture with entire margins on the solid medium and the diameter was reached up to 0.5–1 mm. The grown cells were dispersed in a liquid medium, stained Gram negative, and exhibited rod shape under a scanning electron micrograph (Figure 2). It is recognized by earlier research that microbial load and diversity in the environmental sample depend upon temperature and trace elements. Therefore, analysis of the optimum temperature requirement for microbial growth is one of the most significant parameters that can influence the cellular growth and metabolism (Su, Zhao, and Xia 2018). Accordingly, the optimal temperature for the growth of the isolate was recorded between 26 and 41°C and the highest rate was at 35°C. Further, the strain was sustained between pH 6.5 and 9.0 and the optimum growth was at pH 8.0 (Table 2). The isolate was unable to produce tryptophanase and catalase enzymes; therefore, it showed indole and catalase test negative. The lipase, protease, and starch hydrolyzing activity were also not detected for that strain. However, the cells were capable of resisting selected antibiotics (Penicillin G and Streptomycin) during growth. Dridi et al. (2011) reported that archaea can tolerate penicillin and streptomycin due to the diverse structure of their cell wall. During growth under optimal conditions, the doubling time and specific growth rate were observed to be 12.74 h and 0.023 h−1, respectively (Table 2). Altogether, this metabolic difference was observed due to microbial extremely adaptable function in lifecycle and varied metabolic capacities (Norrell and Messley 2003).