Microbial communities associated with the co-metabolism of free cyanide and thiocyanate under alkaline conditions

Abstract

This study focused on the identification of free cyanide (CDO) and thiocyanate (TDO) degrading microbial communities using a culture-dependent and independent approach. Culturable microbial species were isolated from the CDOs ( = 13) and TDOs ( = 18). The CDOs were largely dominated by sp. while the TDOs were dominated by sp., , sp. and sp. However, 16S rRNA amplicon gene-sequencing revealed the complexity and diversity of the microbial communities in contrast to the organisms that were detected using culture-dependent technique. Overall, the organisms were mainly dominated by and sp. at 37.82 and 30.5% for CDOs, and 35.26 and 17.58% for TDOs, respectively. The co-culturing of the CDOs and TDOs resulted in biochemical changes of key metabolic enzymes, and this resulted in the complete degradation of CN and SCN simultaneously; a phenomenon which has not been witnessed, especially under alkaline conditions. Current ongoing studies are focused on the application of these organisms for the biodegradation of CN and SCN in a continuous system, under changing operational parameters, to assess their effectiveness in the biodegradation of CN and SCN.

Integrated Hydrolysis of Mixed Agro-Waste for a Second Generation Biorefinery Using Nepenthes mirabilis Pod Digestive Fluids

“…In this study, DNA extraction and Polymerase Chain Reaction (PCR) amplification of 16S ribosomal deoxyribonucleic acid (rDNA) was performed in an external laboratory (i.e., Inqaba biotech, Pretoria, South Africa) using the commercial genomic DNA purification kit (Zymo Research; Fungal/Bacterial DNA kit, Irvine, CA, USA), as per the manufacturer's instructions. The genomic DNA of strain was extracted for PCR using universal bacterial primers targeting the 16S rDNA gene [26]. The DNA was assessed using (1) a 0.5% (v/v), i.e., 500 µL per 100 mL, of the genomic lysis buffer, while the cell disruptor was processed at maximum speed for 5 min, subsequently centrifuged at 10,000× g for 1 min in a lysis tube; (2) A volume (400 µL) of supernatant of Zymo-Spin was transferred into a spin filter in a collection tube and was also centrifuged at 7000 rpm for 1 min; (3) A volume (1.2 mL) of Fungal/Bacterial DNA binding buffer was added to the filtrate in the collection tube from Step 2; (4) A volume (800 µL) of the mixture from Step 4 was transferred to a Zymo-Spin column in a collection tube and centrifuged at 10,000× g for 1 min.…”

“…In previous studies, agro-waste, in particular, C. sinensis, M. domestica, corn cobs from Z. mays and Q. robur, had been determined to contain sufficient quantities of extractable fermentable sugars [26,[47][48][49]. Although some produce inhibiting by-products, such as ferulic, glucuronic, p-coumaric, acetic acids and phenolics including residual heavy metals during hydrolysis [10], some of which were hypothetically assumed to be biodegradable using N. mirabilis digestive fluids.…”

Advances in the development and application of microbial consortia for metabolic engineering

“…They allow high-throughput screening and in-depth monitoring of drug effects on cell–cell interactions (Fang and Eglen, 2017; Goers et al., 2014). Co-cultivation strategies have been also applied for efficient degradation of different organic contaminants (Benner et al., 2015; Mekuto et al., 2018; Zhang et al., 2013; Zhao et al., 2016).…”

Characterization of bacterial diversity and assessing the cyanide biodegradation potential of bacterial isolates from gold processing plants

“…Microbial degradation is an attractive technology for cyanide, turning it into a valuable natural tool for environmental purposes [6] and take advantage of the indigenous microorganisms such as bacteria and their ability to use this chemical as a source of nutrients to metabolize it in safer products like CO2, formate, formamide, and methane [7,8]. The diversity and distribution of microorganisms is influenced by the composition of the geochemical matrix of microhabitats and the introduction of toxic or polluting substances that cause changes in the structure, diversity and function of the microbial community associated with the site [9].…”