The aim of this study was to investigate the potential of converting potato peel waste into bio ethanol using an in-house produced multi-enzyme preparation. To achieve this, a variety of pre-treatment strategies, including thermal, chemical, and thermo-chemical methods, were applied to the potato peels. These included boiling for 30 and 60 min, steam at varying pressures and times, and different concentrations of chemicals such as H2SO4, HNO3, CH3COOH, HCl, NaOH, Ca(OH)2, KOH, NH3, and H2O2, either alone or in combination with steam. The pre-treated potato peels were then enzymatically hydrolyzed using a crude multi-enzyme cocktail derived from solid-state fermentation of wheat bran by a natural variety of Aspergillus niger P-19, containing cellulases, hemicellulases, pectinase, and amylases. The most effective pre-treatment combination was found to be 3% H2SO4 followed by steam under pressure and enzymatic hydrolysis using the crude multi-enzyme preparation. This combination resulted in the highest yield of reducing sugars (141.04 ±12.31 g/l) with a 98.49% carbohydrate conversion at a 20% substrate loading, giving an ethanol yield of 43.2 g/l. Furthermore, supplementing the medium with peptone, (NH4)(H2PO4), and ZnSO4 at 0.1%w/v each with 22% and 24% solid, respectively, resulted in appreciable yields of 51.67 and 54.75 g/l, further enhancing the ethanol yield.

No abstract

This study aimed to explore the viability of converting potato peel waste into bioethanol using a custom-produced multi-enzyme preparation. Various pretreatment approaches were employed on the potato peels, including thermal, chemical, and thermo-chemical methods. These methods involved boiling for 30 and 60 min, steaming at different pressures and durations, and applying different concentrations of chemicals, including H2SO4, HNO3, CH3COOH, HCl, NaOH, Ca(OH)2, KOH, NH3, and H2O2, either individually or in combination with steam treatment. The pretreated potato peels were subsequently subjected to enzymatic hydrolysis using a crude multi-enzyme cocktail obtained from solid-state fermentation of wheat bran by a naturally occurring strain of Aspergillus niger P-19. This enzyme cocktail consisted of cellulases, hemicellulases, pectinase, and amylases. The most effective pretreatment combination involved the use of 3% H2SO4 followed by steam treatment under pressure, and enzymatic hydrolysis utilizing the crude multi-enzyme preparation. This combination resulted in the highest concentration of reducing sugars (141.04 ± 12.31 g/L), with a carbohydrate conversion rate of 98.49% when a substrate loading of 20% was used. As a result, an ethanol yield of 43.2 ± 3.82 g/L, representing 21.6% based on dry matter, was achieved. Furthermore, supplementing the medium with peptone, (NH4)(H2PO4), and ZnSO4 at a concentration of 0.1% w/v each, along with solid loadings of 22% and 24%, respectively, achieved yield improvements of 51.67 g/L and 54.75 g/L. However, the maximum productivity of 23.4% was observed with a 22% loading, compared to a yield of 22.8% with a 24% solid loading, based on dry matter.

The study addresses the management of kitchen waste by transforming it into biofertilizer formulations utilizing an effective in-house developed multi-enzyme preparation. A separate hydrolysis and fermentation bioprocessing approach which in particular relates to the application of a separate enzyme preparation from Aspergillus niger P-19 to separately hydrolyze kitchen waste, followed by the growth of Klebsiella pneumoniae AP-407 in the liquid hydrolysate as well with simultaneous production of carrier-based biofertilizer. In liquid and carrier-based biofertilizers, the viable cell count reaches 3.00 × 1012 CFU/ml and 3.00 × 1012 CFU/g, respectively. The current study adopts a novel process technique for the manufacturing of both carrier and liquid biofertilizers, adopting a zero-waste approach to the management of kitchen waste.

This study addresses the management of kitchen waste by transforming it into biofertilizer formulations, utilizing an effective, in-house-developed multi-enzyme preparation. An approach consisting of separate hydrolysis and fermentation bioprocessing processes was used, employing a multi-enzyme preparation from Aspergillus niger P-19 to separately hydrolyze kitchen waste, followed by the fermentation of the hydrolysate for the growth of Klebsiella pneumoniae AP-407, which has biofertilizer traits. This has led to the simultaneous generation of liquid as well as carrier-based biofertilizer formulations with viable cell counts of 3.00 × 1012 CFU/mL and 3.00 × 1012 CFU/g, respectively. Both biofertilizer formulations significantly enhanced the morphometric characteristics and leaf chlorophyll contents of Tagetes erecta, in addition to enriching the soil with essential nutrients. The current study adopted a novel processing technology for the manufacturing of both carrier and liquid biofertilizers, adopting a zero-waste approach for the management of kitchen waste.