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 Pseudomonas 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.

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 Pseudomonas 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.

Microbial community diversity of organically rich cassava sago factory waste waters and their ability to use nitrate and N2O added as external N-sources for enhancing biomethanation and the purification efficiency.

Water shortage necessitated South Indian sago factory owners, extracting starch out of cassava tubers, to install biogas plants where a starch utilizing microbial community multiplies and reduces the biological oxygen demand (BOD) of the waste waters by presently about 30%. The purification efficiency of sago factory waste waters, rich in solid particles and having wide C/N ratios, around 250, through unstirred biogas plants needs to be improved. Our approach was to apply instead of animal slurry nitrate (NO3(-)) and nitrous oxide (N2O) as external N-sources anticipating a better N-distribution in the unstirred biogas plants. Estimated cell numbers, bacterial community changes, on the basis of 16S rRNA gene clone libraries and changing CO2-, CH4-, N2O releases due to the presence of nitrate or N2O suggest that acid tolerant Lactobacillus spp. dominate the biogas plant inflows (pH 3.5). They were very less or not found in the outflows (pH 7.3). Assumingly, the phyla Bacteroidetes (Prevotella spp.), Proteobacteria (Rhizobium spp., Defluvibacter sp.), Firmicutes (Megasphaera spp., Dialister spp., Clostridium spp.) and Synergistetes (Thermanaerovibrio spp.), not-detectable in the biogas plant inflows, replaced them. Anaerobes, about 400cellsml(-1) in the inflows, increased to about 10(6)cellsml(-1) in the outflows. The methane formation, as confirmed by the incubation experiments, suggests that methanogens must have been present among the anaerobes. In the biogas plant in- and outflows also about 300cellsml(-1) denitrifying bacteria and up to 10(4)cfu fungi were found. Despite the low number of denitrifying bacteria nitrate added to the biogas plant in- and outflows was widely consumed and added N2O decreased considerably. Thus, wide C/N ratios substrates like sago factory waste waters keep the N2O emissions low by using N2O either as electron acceptor or by incorporating it into the growing biomass what needs to be confirmed. The biogas plant inflow samples have emitted tentatively more CO2 and the outflow samples released more CH4.

Nanotechnology and patents in agriculture, food technology, nutrition and medicine - advantages and risks: worldwide patented nano- and absorber particles in food nutrition and agriculture.

The keywords nanotechnology, super absorber, agriculture, nutrition, and food technology exhibited 28,149 positive matches under more than 68 million patents worldwide. A closer look at the first 500 nanotechnology, agriculture, nutrition and biotechnology related patents, published during 2011-2012, unveiled that 64% are parts of machines and control devices while about 36% comprise metal oxides, fertilizers, pesticides and drugs, which are compounds and often applied in combination with inorganic or organic super absorbing polymeric structures. The latter compounds are in the focus of this special issue.