Isolation of an Endophytic Cyanide resistant fungus Cunninghamella bertholletiae (original) (raw)
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STUDIES ON CYANIDE DEGRADING FUNGI FROM AGRICULTURAL SOIL
2023
Although cyanide is ubiquitous in the environment, the highest environmental levels are found in the vicinity of combustion sources such as automotive exhaust, fires, cigarette. The research aimed at isolating and identifying fungi species from sandy, and loamy soil capable of metabolizing cyanide by using it as its carbon source. Access the various health hazard associated with exposure to cyanide in animals, plants and humans. Identify the metabolic pathway exhibited by the fungi species while degrading the chemical compound. The future prospects of using fungi strains for cyanide clean-up. The practical was conduct by preparing PDA of 4.8 dissolved in 100ml of distilled water along with 10ml of distilled water dispensed into four testubes and autoclaved. 1g of sandy soil, clay soil and loamy soil were then dispensed into the test tubes by serially diluting and 1ml of the culture was withdrawn and dissolved in the petri-dish and growth was observed after 3-5 days at 25-27 room temperature 0C. MSM was aseptically prepared and adjusted to pH of 5.6. The result showed that the average mean of fungi count in sandy soil was 1.6x104, clay soil was 2.2x104, loamy soil was 1.7x104. The growth on MSM for Aspergillus niger was positive for the cyanide concentration of 0.01g, 0.05g, 0.1g, Aspergilus flavus was positive for the cyanide concentration of 0.01g, 0.05g and negative for 0.1g, Mucor racemosus was negative for the cyanide concentration of 0.01g, 0.05g, 0.1g, and Aspergillus fumigatus was positive for the for the cyanide concentration of 0.01g, 0.05g, 0.1g respectively. it was evident that A. fumigatus, A. niger, A. flavus contains enzymes for the degradation of cyanide as exhibited by their growth within the MSM mixed at varying cyanide concentration of 0.01g, 0.05g, 0.1g. With A. fumigatus the fastest growing fungal isolate remediating the potassium cyanide to formamide by its nitrilases enzyme after 3 days within room temperature of 250C after macroscopic examination of the colonies. Where as Mucor racemosus lacked the essential enzymes such as cyanases or nitrilases for the breakdown of the cyanide contained in the media and was therefore killed by the chemical. Therefore, Aspergillus fumigatus should be greatly considered as a remediation to cyanide wastes as it contain nitrilases able to breakdown cyanide into formamide.
Aerobic cyanide degradation by bacterial isolates from cassava factory wastewater
Ten bacterial strains that utilize cyanide (CN) as a nitrogen source were isolated from cassava factory wastewater after enrichment in a liquid media containing sodium cyanide (1 mM) and glucose (0.2% w/v). The strains could tolerate and grow in cyanide concentrations of up to 5 mM. Increased cyanide levels in the media caused an extension of lag phase in the bacterial growth indicating that they need some period of acclimatisation. The rate of cyanide removal by the strains depends on the initial cyanide and glucose concentrations. When initial cyanide and glucose concentrations were increased up to 5 mM, cyanide removal rate increased up to 63 and 61 per cent by Bacillus pumilus and Pseudomo-nas putida. Metabolic products such as ammonia and formate were detected in culture supernatants, suggesting a direct hydrolytic pathway without an intermediate formamide. The study clearly demonstrates the potential of aerobic treatment with cyanide degrading bacteria for cyanide removal in cassava factory wastewaters.
International Journal of Scientific Research in Chemistry, 2020
Lactic acid bacteria are predominant microorganisms that play important roles during cassava fermentation. Most efforts to develop cyanide tolerant isolates for cassava fermented products have been unsuccessful because of cyanide toxicity in cassava tubers. The objectives of this study was identify cyanide tolerating bacteria and study their tolerability efficiency. 119 lactic acid bacteria were isolated from fermented cassava pulp juice. Out of the total isolated bacteria, ten potential cyanide tolerating bacteria was screened. The cyanide tolerance efficiency was studied at 100, 400, 600 and 8000mg/L potassium cyanide, growth at different temperature and pH were analyzed. The maximum growth rate reading of the screened isolates ranges (0.674 to 1.116) at 600nm in maximum cyanide concentration. Isolate CD1, LA2, LA1 and CD2 showed maximum cyanide tolerance of (74.4, 72.66, 70.66 and 68.73%) respectively at 800mg/l after 48hr of incubation. The cyanide tolerability potential of individual isolates varies across different cyanide concentration. Above all 10 isolates were resistant to maximum cyanide concentration and possess potential of cyanide tolerating properties that help their selection and application in a controlled process to detoxify cassava roots for food and feed utilization.There was a general decrement in all samples over 48h fermentation period from 6.00 to 3.18 and the bacterial isolates showed significant growth at room temperature which were between 25 and 40 °C.
International Journal of Environmental Engineering, 2012
ABSTRACT The capability of six isolated bacterial strains to utilise cyanide in cassava mill wastewater as a nitrogen source in a batch bioreactor was examined and evaluated. The results revealed that all the isolates were capable of degrading cyanide with percent degradation between 60 and 94% in 96 h. There was high positive correlation between cyanide biodegradation and microbial growth (0.90 ≤ R² ≤ 0.97). The Monod kinetic model adequately described the dynamic behaviour of cyanide degradation by the different bacterial isolates. Thus, the study revealed the possibility of using the bacterial isolates in the biotreatment of cyanide waste effluents.
BIOLOGICAL REMEDIATION OF CYANIDE: A REVIEW
Cyanide and its complexes are produced by industries all over the world as waste or effluents. Biodegradation is considered to be the cheapest and the most effective method to clean-up cyanide from the environment. Several studies on different types of microorganisms that can degrade cyanide in the environment have been carried out. Hydrolytic, oxidative, reductive and substitutive/transfer reactions are some of the common pathways used by microorganisms in cyanide degradation. Biodegradation of cyanide can occur aerobically or anaerobically depending on the environmental conditions. Immobilized enzymes or microorganisms prove to be very effective method of degradation. Microorganisms such as , , , Klebsiella oxytoca Corynebacterium nitrophilous Brevibacterium nitrophilous Bacillus spp., spp. and UKMP-5M have been reported to be very effective in biodegradation of