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This study investigated the feasibility of anaerobic digestion (AD) of potato peel waste (PPW) and its lactic acid fermentation residue (PPW-FR) for methane (CH 4 ) production. The experimental results showed that about 60–70% CH 4 content was obtained. The digester using PPW-FR as feedstock exhibited better performance and produced a highest cumulative CH 4 production of 273 L/kg VS fed , followed by 239 L/kg VS fed using PPW under the same conditions. However, with increasing solid loadings of PPW-FR feedstock from 6.4% to 9.1%, the CH 4 production was inhibited. The generation, accumulation, and degradation of volatile fatty acids (VFAs) in digesters were also investigated in this research. [ABSTRACT FROM AUTHOR]

Lactic acid (LA) is a necessary industrial feedstock for producing the bioplastic, polylactic acid (PLA), which is currently produced by pure culture fermentation of food carbohydrates. This work presents an alternative to produce LA from potato peel waste (PPW) by anaerobic fermentation in a sequencing batch reactor (SBR) inoculated with undefined mixed culture from a municipal wastewater treatment plant. A statistical design of experiments approach was employed using set of 0.8 L SBRs using gelatinized PPW at a solids content range from 30 to 50 g L −1 , solids retention time of 2–4 days for yield and productivity optimization. The maximum LA production yield of 0.25 g g −1 PPW and highest productivity of 125 mg g −1 d −1 were achieved. A scale-up SBR trial using neat gelatinized PPW (at 80 g L −1 solids content) at the 3 L scale was employed and the highest LA yield of 0.14 g g −1 PPW and a productivity of 138 mg g −1 d −1 were achieved with a 1 d SRT. [ABSTRACT FROM AUTHOR]

Potato peel waste (PPW) as zero value byproduct generated from food processing plant contains a large quantity of starch, non-starch polysaccharide, lignin, protein, and lipid. PPW as one promising carbon source can be managed and utilized to value added bioproducts through a simple fermentation process using undefined mixed cultures inoculated from wastewater treatment plant sludge. A series of non-pH controlled batch fermentations under different conditions such as pretreatment process, enzymatic hydrolysis, temperature, and solids loading were studied. Lactic acid (LA) was the major product, followed by acetic acid (AA) and ethanol under fermentation conditions without the presence of added hydrolytic enzymes. The maximum yields of LA, AA, and ethanol were respectively, 0.22 g g −1 , 0.06 g g −1 , and 0.05 g g −1 . The highest LA concentration of 14.7 g L −1 was obtained from a bioreactor with initial solids loading of 60 g L −1 at 35 °C. [ABSTRACT FROM AUTHOR]