Pre-treatment of agro-industrial wastes used as alternative nutrients for rearing Cydia pomonella

The physico-chemical and nutritional potential of starch industry wastewater (SIW), brewery wastewater (BWW) and apple pomace sludge (POM) and municipal wastewater sludge (WWS) were compared. The results showed higher nutrient content for BWW (19.52 ± 2.1 g l−1 [proteins], 9.17 ± 1.5 g l−1 [carbohydrates] and 0.25 ± 0.1 g l−1 [lipids]) and POM (16.1 ± 1.3 g l−1 [proteins], 8.2 ± 1.3 g l−1 [carbohydrates] and 0.15 ± 0.2 g l−1 [lipids]), and lower concentration of toxic elements (metals) for BWW (0.005 ± 0.0004 mg kg−1 [Cd], 0.003 ± 0.0002 mg kg−1 [Pb], 0.021 ± 0.003 mg kg−1 [Al] and 1.66 ± 0.2 mg kg−1 [Fe]) and POM (0.002 ± 0.0002 mg kg−1 [Cd], 0.0014 ± 0.0001 mg kg−1 [Pb], 0.019 ± 0.002 mg kg−1 [Al] and 1.61 ± 0.2 mg kg−1 [Fe]) as compared to SIW (5.1 ± 0.5 g l−1 [protein], 7.5 ± 0.8 g l−1 [carbohydrate], 0.13 ± 0.01 g l−1 [lipid], 0.003 ± 0.0003 mg kg−1 [Cd], 0.0025 ± 0.0002 mg kg−1 [Pb], 0.021 ± 0.003 mg kg−1 [Al] and 1.66 ± 0.2 mg kg−1 [Fe]) and WWS (7.8 ± 0.9 g l−1 [protein], 6.7 ± 0.7 g l−1 [carbohydrate], 0.12 ± 0.01 [lipid] and 5.6 ± 0.6 mg kg−1 [Cd], 138.6 ± 13.9 mg kg−1 [Pb], 1758 ± 176 mg kg−1 [Al] and 10782 ± 1080 mg kg−1 [Fe]). To increase the nutritional potential and improve the rheological characteristics pre-treatment was carried out. Hydrolysis of BWW and POM was performed at pH (initial, neutral and alkaline-10), at different temperatures (80 °C, 100 °C and 121 °C) and time periods (15, 30, and 45 min). Hydrolysis at 100 °C for 30 min proved effective for breeding of larvae for BWW and POM wastes.