Culture optimization for production and characterization of bioflocculant by Aspergillus flavus grown on chicken viscera hydrolysate.

The economics of bioflocculant production is coupled with the use of a low-cost substrate at appropriate culture conditions. The use of a waste substrate for this purpose offers an additional treatment measure to mitigate environmental pollution. We investigated the growth of Aspergillus flavus and its bioflocculant yield using chicken viscera hydrolysate as the sole media. The effects of culture conditions including time, pH, shaker speed, temperature and inoculum size on bioflocculant production were all investigated and optimised through response surface method based on the central component design (CCD) package of Design Expert. Next, the purified bioflocculant was physically and chemically characterised. Under optimised culture conditions (incubation time 72 h, pH 7, shaker speed 150 rpm, temperature 35 °C and inoculum 4%), 6.75 g/L yield of crude bioflocculant was recorded. The bioflocculant activity was mostly distributed in the cell-free supernatant with optimum efficiency of 91.8% at a dose of 4 mL/100 mL Kaolin suspension. The purified bioflocculant was a glycoprotein consisting of 23.46% protein and 74.5% sugar, including 46% neutral sugar and 2.01% uronic acid. The X-ray photoelectron spectroscopy fundamental analysis of the purified bioflocculant indicated that the mass proportion of C, O and N, were 63.46%, 27.87% and 8.86%, respectively. The bioflocculant is mainly composed of carbonyl, amino, hydroxyl, and amide functional groups. This study for the first time indicates a high potential of bioflocculant yield from chicken viscera at the appropriate culture conditions.

Development of a new culture medium for bioflocculant production using chicken viscera.

The economy of mass bioflocculant production and its industrial application is couple with the cost of production. The growth medium is the most significant factor that accounts for the production cost. In order to find a substitute for the expensive commercial media mostly the carbon and nitrogen sources used for bioflocculant production, we use chicken viscera as a sole source of nutrient for bioflocculant production. The culture conditions for Aspergillus flavus S44-1 growth and bioflocculant yield were optimized through one factor at a time (OFAT). The use of chicken viscera as a sole source to develop a culture medium seems to be more appropriate, simple, reduce cost of bioflocculant production and in addition offers a sustainable means of managing environmental pollution by the poultry waste. In this article, we focus on detailed description of the steps involve in developing an optimized culture medium using chicken viscera as a sole source for bioflocculant production. •A new media for bioflocculant production was developed from chicken viscera.•The culture conditions for bioflocculant production were determined and optimized.•The bioflocculant yield and efficiency were parallel to mycelial weight at log phase.

Implications for industrial application of bioflocculant demand alternatives to conventional media: waste as a substitute.

The biodegradability and safety of the bioflocculants make them a potential alternative to non-biodegradable chemical flocculants for wastewater treatment. However, low yield and production cost has been reported to be the limiting factor for large scale bioflocculant production. Although the utilization of cheap nutrient sources is generally appealing for large scale bioproduct production, exploration to meet the demand for them is still low. Although much progress has been achieved at laboratory scale, Industrial production and application of bioflocculant is yet to be viable due to cost of the production medium and low yield. Thus, the prospects of bioflocculant application as an alternative to chemical flocculants is linked to evaluation and utilization of cheap alternative and renewable nutrient sources. This review evaluates the latest literature on the utilization of waste/wastewater as an alternative substitute for conventional expensive nutrient sources. It focuses on the mechanisms and metabolic pathways involved in microbial flocculant synthesis, culture conditions and nutrient requirements for bioflocculant production, pre-treatment, and also optimization of waste substrate for bioflocculant synthesis and bioflocculant production from waste and their efficiencies. Utilization of wastes as a microbial nutrient source drastically reduces the cost of bioflocculant production and increases the appeal of bioflocculant as a cost-effective alternative to chemical flocculants.