Improved biomass production by humic analog anthraquinone-2-sulfonate from kitchen waste in a two-phase system

Abstract

Fermentation products of volatile fatty acids from kitchen waste were explored as substrates of anoxygenic photosynthetic bacteria (APB) in a dark-photo fermentation reactor, and anthraquinone-2-sulfonate (AQS) was firstly applied in photofermentation process to boost the biomass yield. During the hydrolysis and acidification phase, the production of SCOD and volatile fatty acids (VFAs) reached 75.26 g L⁻¹ and 14.2 g L⁻¹ within 72 h, respectively. During the photofermentation phase, the VFAs and NH₃–N removal rate in AQS test was 1.44- and 3.0-fold higher than that of control test without AQS addition, respectively. Additionally, AQS increased biomass production by 120% (0.46 g biomass/g COD) than that of control test (0.21 g biomass/g COD). Pyrosequencing results revealed that AQS lead to the highest bacterial diversity and abundance of purple non-sulfur bacteria (22.9%) and denitrifier (8.5% of Planctomyces). This study successfully established synergetic biomass production from fermentation products of kitchen waste with aid of AQS.