A hot topic: thermophilic plastic biodegradation.

Biological degradation of plastic waste is an environmentally and economically friendlier alternative to current recycling practices and enables the cycling of plastic monomers back into virgin-quality plastics. However, due to slow reaction rates, there is a lack of an industrially viable biodegradation strategy for most plastics. Here, we highlight the applicability of a thermophilic biodegradation strategy over a mesophilic approach, to enhance enzyme accessibility and catalyze plastic biodegradation.

Development of simple, scalable protease production from Botrytis cinerea.

Heat haze-forming proteins are stable during winemaking and are typically removed via adsorption to bentonite. Proteolytic degradation is an alternative method to prevent wine-haze and offers the opportunity to reduce the environmental impacts and labor cost of the process. Herein, we describe the development of a production system for Botrytis cinerea proteases for the enzymatic degradation of heat haze-forming proteins.

Mild fractionation of sugarcane bagasse into fermentable sugars and β-O-4 linkage-rich lignin based on acid-catalysed crude glycerol pretreatment.

Acid-catalysed crude glycerol (ACG) pretreatment was carried out at 110 °C and 130 °C for mild fractionation of sugarcane bagasse into fermentable sugars and high-quality lignin. ACG pretreatment at 110 °C led to sugar yields of 71%-74%, comparable to those with acid-catalysed reagent-grade glycerol (AG). ACG pretreatment removed more lignin (53%-75%) than AG pretreatment (38%-49%), likely due to the presence of organic impurities in ACG.

Scale-up of two-step acid-catalysed glycerol pretreatment for production of oleaginous yeast biomass from sugarcane bagasse by Rhodosporidium toruloides.

Two-step dilute acid and acid-catalysed glycerol pretreatment was developed to maximise sugar yield from sugarcane bagasse. At the laboratory scale, dilute acid pretreatment at 130 °C followed by acid-catalysed glycerol pretreatment at 170 °C led to a total sugar (C5 + C6) yield of 82%, 31% higher than that from one-step acid-catalysed glycerol pretreatment. At the pilot scale, the two-step dilute acid and acid-catalysed glycerol pretreatment led to a maximum sugar yield of 74%, 13% higher than that from one-step pretreatment with 52% reduction in glycerol usage.

Effective degradation of polychlorinated biphenyls by a facultative anaerobic bacterial consortium using alternating anaerobic aerobic treatments.

Polychlorinated biphenyls (PCBs) are synthetic mixtures of chlorinated hydrocarbon compounds that were widely used in the past and still found in the environment due to their highly recalcitrant nature. A combination of anaerobic dechlorination and aerobic oxidation is essential to degrade these PCB mixtures into less toxic products. It was hypothesized that due to the complexity of PCB mixtures, a consortium of carefully selected suitable microbial species will perform better than the application of individual microbes.