Strategies to boost anaerobic digestion performance of cow manure: Laboratory achievements and their full-scale application potential.

The pretreatment of lignocellulosic biomass (LC biomass) prior to the anaerobic digestion (AD) process is a mandatory step to improve feedstock biodegradability and biogas production. An important potential is provided by lignocellulosic materials since lignocellulose represents a major source for biogas production, thus contributing to the environmental sustainability. The main limitation of LC biomass for use is its resistant structure. Lately, biological pretreatment (BP) gained popularity because they are eco-friendly methods that do not require chemical or energy input. A large number of bacteria and fungi possess great ability to convert high molecular weight compounds from the substrate into lower mass compounds due to the synthesis of microbial extracellular enzymes. Microbial strains isolated from various sources are used singly or in combination to break down the recalcitrant polymeric structures and thus increase biogasgeneration. Enzymatic treatment of LC biomass depends mainly on enzymes like hemicellulases and cellulases generated by microorganisms. The articles main purpose is to provide an overview regarding the enzymatic/biological pretreatment as one of the most potent techniques for enhancing biogas production.

Microorganisms and Enzymes Used in the Biological Pretreatment of the Substrate to Enhance Biogas Production: A Review

Antibiotic is widely present in the effluent from livestock husbandry and the pharmaceutical industry. Antibiotics in wastewater usually have high biological toxicity and even promote the occurrence and transmission of antibiotic resistant bacteria and antibiotic resistance genes. Moreover, most antibiotic-containing wastewatercontains highconcentration of ammonia nitrogen. Improper treatment will lead to high risk to the surrounding environment and even human health. The anaerobic ammonium oxidation (anammox) with great economic benefit and good treatment effect is a promising process to remove nitrogen from antibiotic-containing wastewater. However, antibiotic inhibition has been observed in anammox applications. Therefore, a comprehensive overview of the single and combined effects of various antibiotics on the anammox system is conducted in this review with a focus on nitrogen removal performance, sludge properties, microbial community, antibiotic resistance genes and anammox-involved functional genes. Additionally, the influencing mechanism of antibiotics on anammox consortia is summarized. Remaining problems and future research needs are also proposed based on the presented summary. This review provides a better understanding of the influences of antibiotics on anammox and offers a direction to remove nitrogen from antibiotic-containing wastewater by the anammox process.

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A review on anammox process for the treatment of antibiotic-containing wastewater: Linking effects with corresponding mechanisms

Lignocellulosic biomass is one of the most abundant renewable resources, and their transformation into bioenergy is an effective approach to alleviate energy shortage and recycle organic wastes. This review summarized the rumen microorganisms and related enzymes, and rumen digestion strategies and mechanisms for improvement of anaerobic rumen digestion in engineering application. Main related literatures were searched on sciencedirect and web of science, systematically summarized, compared and analyzed. Rumen microorganisms accomplish the hydrolysis, acidogenisis and methanogenesis of lignocellulosic biomass, which mainly depends on the synergy of microorganisms and enzymes. Rumen bacteria are the main players and anaerobic fungi play an indispensable role in the hydrolysis and acidogenesis of lignocelluloses. The interaction of different microorganisms promotes the efficiency of lignocelluloses conversion to renewable energy in rumen digestion system, especially protozoa and methanogens. Rumen microorganisms secrete the cellulases, hemicellulases and ligninases, which have their own unique structure and action mode and synergistically promote the lignocellulose degradation. Anaerobic digestion reactor cannot be simply designed through simulating the rumen structure and environment, while the simulation of rumen digestion strategies according to the physicochemical properties and microbial community is more important. The substrate structure and additives significantly improve the rumen digestion of lignocellulosic biomass as a potential design strategy. Finally, the current challenges, future works, and prospects on biological conversion of lignocellulose to bioenergy with rumen microorganisms are outlined.

Promising biological conversion of lignocellulosic biomass to renewable energy with rumen microorganisms: A comprehensive review

Flocculation of different types of combined contaminants of antibiotics and heavy metals by thermo-responsive flocculants with various architectures

Persistent action of cow rumen microorganisms in enhancing biodegradation of wheat straw by rumen fermentation.

Cow manure as additive to a DMBR for stable and high-rate digestion of food waste: Performance and microbial community.

Inhibitory effects of heavy metals and antibiotics on nitrifying bacterial activities in mature partial nitritation.

Stable and high-rate anaerobic co-digestion of food waste and cow manure: Optimisation of start-up conditions.

Effects of long-term acclimatization on the optimum substrate mixture ratio and substrate to inoculum ratio in anaerobic codigestion of food waste and cow manure.

Bao-Shan Xing

Papers

Persistent action of cow rumen microorganisms in enhancing biodegradation of wheat straw by rumen fermentation.

Cow manure as additive to a DMBR for stable and high-rate digestion of food waste: Performance and microbial community.

Inhibitory effects of heavy metals and antibiotics on nitrifying bacterial activities in mature partial nitritation.

Stable and high-rate anaerobic co-digestion of food waste and cow manure: Optimisation of start-up conditions.

Effects of long-term acclimatization on the optimum substrate mixture ratio and substrate to inoculum ratio in anaerobic codigestion of food waste and cow manure.