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 L1
, solids retention time of 2–4 days for yield and productivity
optimization. The maximum LA production yield of 0.25 g g1 PPW and highest productivity of
125 mg g1 d1 were achieved. A scale-up SBR trial using neat gelatinized PPW (at 80 g L1 solids content)
at the 3 L scale was employed and the highest LA yield of 0.14 g g1 PPW and a productivity of
138 mg g1 d1 were achieved with a 1 d SRT.