The open reading frame alr1585 of Anabaena sp. strain PCC 7120 encodes a heme-dependent peroxidase (Anabaena peroxidase [AnaPX]) belonging to the novel DyP-type peroxidase family (EC 1.11.1.X). We cloned and heterologously expressed the active form of the enzyme in Escherichia coli. The purified enzyme was a 53-kDa tetrameric protein with a pI of 3.68, a low pH optima (pH 4.0), and an optimum reaction temperature of 35°C. Biochemical characterization revealed an iron protoporphyrin-containing heme peroxidase with a broad specificity for aromatic substrates such as guaiacol, 4-aminoantipyrine and pyrogallol. , respectively. In contrast, the decolorization activity of AnaPX toward azo dyes was relatively low but was significantly enhanced 2-to ϳ50-fold in the presence of the natural redox mediator syringaldehyde. The specificity and catalytic efficiency for hydrogen donors and synthetic dyes show the potential application of AnaPX as a useful alternative of horseradish peroxidase or fungal DyPs. To our knowledge, this study represents the only extensive report in which a bacterial DyP has been tested in the biotransformation of synthetic dyes.

Insects such as the black soldier fly (BSF; Hermetia illucens) are currently being promoted as an alternative protein source for animals and organic waste management agents. To play the dual roles sustainably, there is need to reduce reliance on wild BSF and develop an appropriate farming methodology for the insect. This study aimed at improving larvae production in a black soldier fly colony previously established from the wild in Kenya. The study explored the effect of four locally available organic wastes as feedstocks for production the black soldier fly larvae. Separate feeding trials on faecal sludge (FS), banana peelings (BP), brewer’s waste (BW) and restaurant food waste (FR) was done and their effect on BSF larvae growth rate, larvae weight, total prepupal yield in grams, crude protein and lipid (ether extract) content analysed. The efficiency of the BSF larvae to consume and therefore reduce the waste load of the different substrates was also evaluated. Results showed that BSF larvae fed on FR had significantly higher (P<0.05) total mean yield and average individual weight of 196.9±4.0 g and 0.101±0.002 g, respectively, followed by BW (154.8±6.5 g, 0.078±0.02 g), FS (138.7±5.0 g, 0.070±0.001 g) and with BP the lowest (108.9±5.6 g, 0.055±0.002 g). The harvested BSF larvae crude protein was significantly higher for FS and BW at 45.4±0.1% and 43.0±1.0%, respectively. However, ether extract content was variable and dependent on feedstock used with lower values reported for FS and BW (18.1±0.3% and 27.2%, respectively), and highest for food remains prepupa (36%). Dry matter reduction ranged between 50.3-81.8% with corresponding bioconversion and feed conversion rates ranging from 14.9-20.8% and 2.6-4.5, respectively, was achieved for the substrates used. These results indicated the potential of utilising BSF composting in valorisation of the local organic wastes for their bioremediation from the environment. Due to their availability in large quantities and their low cost, these organic wastes can form important feedstock resources for the sustainable production of BSF larvae as a future alternative protein source for both animal feeds at farm level and industrial scale. In conclusion, embracing nutrient recycling through BSF technology by resource-constrained farmers in Kenya will contribute to food security through supply of proteins for production of poultry and fish.

Edible insects, particularly crickets, are becoming popular due to their nutritional value and efficiency in foodconversion. An increasing number of farmers in Kenya are seeking information on rearing crickets (Orthoptera:Gryllidae) for food and feed. The locals are gradually embracing Acheta domesticus and Gryllus bimiculatus as the species of choice. This paper discusses how cricket farming was introduced to farmers in Bondo and Kabondo in Kenya. The initial crickets were picked from their natural habitat and carefully selected for domestication. Theselected crickets were fed on vegetables and chicken mash and bulked in plastic cages. The insects were carefully nurtured to lay eggs and a large colony was formed for multiplication purposes. Upon maturity, proximate analysiswas done to determine their nutritional value. Some were processed into different dishes for human consumption. Products were subjected to microbial tests at the Kenya Bureau of Standards to verify safety for human consumption. Consumers were invited to taste the processed products. After 3 years into the project, about 50 farmers haveembraced cricket farming around the Lake Victoria region. A. domesticus proved easy for rearing at household levelconditions. Food nutrients identified on dry weight were: 47% protein, 10% carbohydrates, and 25% fat. Minerals included sodium (8,502 µg/g), copper (29.4 µg/g), calcium (3,147.7 µg/g), potassium (9,797.5 µg/g), iron (51.8 µg/g), phosphorus (331.3 µg/g), manganese (58.7 µg/g) and zinc (21.8 µg/g). Vitamins included vitamin A (retinol; 0.35 µg/g), vitamin B2 (riboflavin; 6.3 µg/g), vitamin B1 (thiamine; 15.2 µg/g), and vitamin E (331 µg/g). Children were particularly attracted to biscuits and the fried foods such as fritters, samosa and pancakes. Cricket farming can be embraced as a mini-livestock by farmers in varied agro-ecological conditions in the lake region in Kenya. However, increased consumption of crickets to ensure food security is yet to be observed.

Industrial effluents with high concentrations of toxic heavy metals are of great concern because of their persistence and non-degradability. However, poor operation and maintenance of wastewater treatment infrastructure is a great concern in South Africa. In this study, physico-chemical parameters and heavy metals (HMs) concentration of wastewater from five different industries, Leeuwkuil wastewater treatment plant (WWTP) inflow and effluent, and Vaal River water samples were monitored between January and September 2017, to investigate the correlation between heavy metal pollution and the location of industries and ascertain the effectiveness of the municipal WWTP. Physico-chemical variables such as pH, biological oxygen demand (BOD), dissolved oxygen (DO), chemical oxygen demand (COD), total dissolved solids (TDS) and electrical conductivity (EC) exhibited both temporal and spatial variations with the values significantly higher in the industrial samples. Inductively coupled plasma optical emission spectrometry (ICP-OES) results also showed that aluminium (Al), copper (Cu), lead (Pb) and zinc (Zn) were significantly higher in industrial effluents (p < 0.05), with only Zn and Al exhibiting significant seasonal variability. Statistical correlation analysis revealed a poor correlation between physicochemical parameters and the HMs compositional quality of wastewater. However, toxic HMs (Zn, Cu and Pb) concentrations in treated wastewater from WWTP were above the permissible limits. Although the WWTP was effective in maintaining most of the wastewater parameters within South African Green drop Standards, the higher Cu, Zn, Pb and COD in its final effluent is a concern in terms of Vaal river health and biological diversity. Therefore, we recommend continuous monitoring and maintenance of the WWTPs infrastructure in the study area.