Improved conversion of residual MSW biomass waste to sugars using online process monitoring and integrated contamination control

Enzymatic saccharification of lignocellulosic biomass to soluble sugars is vulnerable to microbial contamination. Identification of early stage indicators of contamination could allow for more rapid intervention and improved sugar retention. Here we validate the use of dissolved oxygen (DO) and pH as early-stage indicators, and used to evaluate the effectiveness of several antimicrobial agents (sodium azide, benzisothiazolinone, hydrogen peroxide and tetracycline). It was found that benzisothiazolinone (BIT) and sodium azide performed most favourably (8.93 and 9.89 g glucose/L, respectively), controlling contamination for the entire 24 hour time course assessed. We then describe the development of a novel integrated control system with online monitoring of DO/pH and automatic administration of a discrete doses of antimicrobial agent to the reaction once environmental DO dropped below a pre-defined threshold. Further, we show that FTIR can be used for continuous real-time glucose quantification during enzyme hydrolysis as an alternative to traditional offline measurement methods.