Enhancement of landfill leachate treatment using extracellular polymeric substances as bio-flocculants.

Fermentation of Klebsiella pneumoniae was conducted using crude glycerol fortified with secondary paper mill sludge as a carbon source in 5 L fermenter. After 96 hours of fermentation, the fermented broth contained mostly microbial cells surrounded by extracellular polymeric substances (EPS) and other particulate residues from paper mill sludge and glycerol. When this fermented broth is used as it is, it is called broth EPS (B-EPS). When the fermented broth is centrifuged, the supernatant solution is separated from the rest of the microbial cells and from sludge residues. This supernatant is called Slime-EPS (S-EPS). Both types of EPS were used for treatment of landfill leachate. S-EPS showed better flocculation activity (85%) than B-EPS (70%). EPS was also used in combination of Al2(SO4)3 or FeSO4. The removal efficiency of COD with use of S-EPS combined with FeSO4 (more than 80% of COD removal) was higher than with S-EPS alone (48% of COD removal). Better results were recorded when S-EPS (0.015 g/L) was combined with FeSO4 (2 g/L) at pH 8. A remarkable reduction of the following parameters was recorded: COD (82%), total nitrogen (44%), phosphorus (50%) and removal of metals such as Ca (64.3%) and Mg (62.4%).

Biopesticide and formulation processes based on starch industrial wastewater fortified with soybean medium.

The aim of this study was to produce Bacillus thuringiensis-based biopesticide using starch-producing industry wastewater (SIW) fortified with soybean medium and optimize the formulated product using different adjuvants. This study was necessary as low endotoxin concentration is obtained in formulated biopesticide when SIW alone is used as fermentation medium. The fermentation runs were conducted using SIW alone and SIW fortified with 25% soybean (w/v) medium in 2000 L and 150 L bioreactor, respectively. SIW supplemented with soybean medium showed an increase in cell count (from 1.95 × 108 to 1.65 × 109 CFU mL-1), spore synthesis (from 1.5 × 108 to 1.35 × 109 CFU mL-1) and endotoxin concentration (from 436 to 1170 µg mL-1) when compared to SIW medium alone. The fermented broth was concentrated using continuous centrifugation and adjuvants were added for biopesticide formulation in order to enhance its resistance against UV rays and rainfastness. Entomotoxicity of the formulation produced using fermented broth of SIW fortified with soybean (38,000 IU µL-1) was higher than that obtained by SIW medium alone (21,000 IU µL-1), commercial biopesticide Foray 76B (20,000 IU µL-1) and Btk sander's (12,500 IU µL-1).

Production of Bacillus thuringiensis based biopesticide formulation using starch industry wastewater (SIW) as substrate: A techno-economic evaluation.

In this study, cost simulation was made to produce Bacillus thuriengiensis based biopesticide formulation using starch industry wastewater (SIW) as substrate. The results obtained at pilot plant (2000L capacity fermenter) were used for cost simulation of the process. The unit production cost for annual production of 5 million L of formulated biopesticide (20.2 Billion International Units (BIU)/L) was estimated to be $ 2.54/L, which is competitive to chemical pesticides. The techno-economic evaluation revealed that the profitability of the biopesticide manufacturing process was sensitive to the plant capacity and selling price of the biopesticide. The manufacturer should target 5 million L annual plant capacity and selling price of $ 15/L for payback period to be less than 5 years. The process serves many advantages (1) alternate disposal or bio-valorisation of industry wastewater and (2) use of industry wastewater as inexpensive carbon source reducing cost of raw materials for fermentation.

Pilot-scale biopesticide production by Bacillus thuringiensis subsp. kurstaki using starch industry wastewater as raw material.

Pilot-scale Bacillus thuringiensis based biopesticide production (2000 L bioreactor) was conducted using starch industry wastewater (SIW) as a raw material using optimized operational parameters obtained in 15 L and 150 L fermenters. In pilot scale fermentation process the oxygen transfer rate is a major limiting factor for high product yield. Thus, the volumetric mass transfer coefficient (KLa) remains a tool to determine the oxygen transfer capacity [oxygen utilization rate (OUR) and oxygen transfer rate (OTR)] to obtain better bacterial growth rate and entomotoxicity in new bioreactor process optimization and scale-up. This study results demonstrated that the oxygen transfer rate in 2000 L bioreactor was better than 15 L and 150 L fermenters. The better oxygen transfer in 2000 L bioreactor augmented the bacterial growth [total cell (TC) and viable spore count (SC)] and delta-endotoxin yield. Prepared a stable biopesticide formulation for field use and its entomotoxicity was also evaluated. This study result corroborates the feasibility of industrial scale operation of biopesticide production using starch industry wastewater as raw material.