which has been
regarded as one promising, efficient, and environmental friendly
solution because starch can be converted into LA directly with no
greenhouse gas CO2 emission during the fermentation process.
Recent studies also revealed that homogeneous LA producing bacteria
can be formed during the undefined mixed culture fermentation
process (Dreschke et al., 2015; Liang et al., 2015; Probst et al.,
2015), which provided solid evidence of LA production from PPW
and other waste stream such as sewage sludge.