Process performance determination data in thiocyanate biodegradation systems: Use of sulphate production

This data article presents the utilization of sulphates as an indirect technique for the assessment of microbial growth, activity and SCN- biodegradation efficiency since the TDO were observed to be unable to utilise the produced sulphates as a source of sulphur (Mekuto e al., 2017) [1] The TDO demonstrated complete SCN- biodegradation while also utilizing the produced ammonium. The production of SO42- from SCN- biodegradation had a good correlation in comparison to the traditional methods of assessing microbial growth and activity i.e. direct cell counts (DCC), heterotrophic counts (CFU) and fluorescein production from fluorescein diacetate (FDA). The concentration of the produced SO42- demonstrated a similar logarithmic trend with the FDA, DCC and CFU techniques, thus confirming that the production of SO42- from SCN- biodegradation systems can be utilised as an indirect technique for the assessment of microbial growth, activity and SCN- biodegradation performance.


b s t r a c t
This data article presents the utilization of sulphates as an indirect technique for the assessment of microbial growth, activity and SCNbiodegradation efficiency since the TDO were observed to be unable to utilise the produced sulphates as a source of sulphur (Mekuto e al., 2017) [1] The TDO demonstrated complete SCNbiodegradation while also utilizing the produced ammonium. The production of SO 4 2from SCNbiodegradation had a good correlation in comparison to the traditional methods of assessing microbial growth and activity i.e. direct cell counts (DCC), heterotrophic counts (CFU) and fluorescein production from fluorescein diacetate (FDA Data accessibility Data is available in the article

Value of the data
This research data provides a rapid microbial performance assessment technique in thiocyanate biodegradation systems.
The data can be utilized by researchers who are active in the development of a robust biological method for the bioremediation of thiocyanate that originates from mining, gasification and coking wastewaters.
The presented data had a good correlation with the tested traditional techniques that are commonly utilized in microbiology and hence it can be utilized as an indicator for thiocyanate biodegradation process performance.

Data
The data presented here demonstrates the utilization of sulphates as an indirect determination of thiocyanate biodegradation systems' performance. Table 1 demonstrates the biodegradation of SCNby the TDO with the subsequent production of ammonium while Fig. 1 illustrates the production of sulphates in comparison to the tested traditional microbial growth/activity techniques.

Microbial culture and growth conditions
Thiocyanate degrading organisms (TDO) were isolated from SCNcontaining wastewater. The TDOs were identified using the 16S rRNA amplicon gene sequencing approach to reveal the bacterial species that were present within the organisms [1]. The procedure and data that was utilised to identify the TDOs were published in [2]. The culture was grown in minimal media as described in [3]. The media was supplemented with SCN -, to achieve a concentration of 150 mg SCN -/L. The flasks were incubated in an orbital shaker at 30°C and 180 rpm. Samples were collected at various time intervals and centrifuged at 10,000g for 5 min prior to the analysis of SCNand SO 2− 4 . SCNbiodegradation and SO 2− 4 production was evaluated using the ferric iron method [4] and turbidimetrically using barium salts [5] respectively. NH 4 þ nitrogen was determined according to the method developed elsewhere [6]. The effect of the initial SCNconcentration on SO 2− 4 production, microbial growth and activity was also assessed in batch cultures for a period of 98 h.

Assessing microbial activity using fluorescein diacetate (FDA)
The microbial activity of the microbial cultures within the biodegradation processes was assessed using the FDA method described in [7]. Briefly, this method works on the hydrolysis of FDA intracellularly by active microorganisms, releasing a fluorescent fluorescein which can be detected spectrophotometrically [8].

Heterotrophic plate counting
The number of viable cells were estimated using the heterotrophic plate count procedure. The plate count procedure was achieved with autoclaved nutrient agar (Meat extract 1.0 g/L, peptone 5.0 g/L, yeast extract 2.0 g/L, NaCl 8.0 g/L, agar 15 g/L). Samples were collected particular intervals and an aliquot (200 µL) of the culture was spread plated after appropriate dilutions. This was followed by incubation at 30°C for 48 h. The visible microbial colonies were counted as colony forming units (CFU).

Direct cell counting (DCC)
DCC was achieved by the utilisation of a Thoma counting chamber (Hawksley, UK). 5 µl of the planktonic microorganisms sampled from the SCNdegradation experiments were evenly distributed in the chamber and counted directly in an Olympus CX21 phase contrast light microscope (New York, U.S.A.). The mobile cells were the only cells that were counted as these were considered to be active and/or viable while the non-mobile cells were ignored as they were considered to be non-viable or dead.