Microbial valorization of underutilized and nonconventional waste streams

Abstract

The growing burden of waste disposal coupled with natural resource scarcity has renewed interest in the remediation, valorization, and/or repurposing of waste. Traditional approaches such as composting, anaerobic digestion, use in fertilizers or animal feed, or incineration for energy production extract very little value out of these waste streams. In contrast, waste valorization into fuels and other biochemicals via microbial fermentation is an area of growing interest. In this review, we discuss microbial valorization of nonconventional, aqueous waste streams such as food processing effluents, wastewater streams, and other industrial wastes. We categorize these waste streams as carbohydrate-rich food wastes, lipid-rich wastes, and other industrial wastes. Recent advances in microbial valorization of these nonconventional waste streams are highlighted, along with a discussion of the specific challenges and opportunities associated with impurities, nitrogen content, toxicity, and low productivity.

Keywords: Industrial waste; Inhibitors; Microbial valorization; Pretreatment.

Fig. 1

Graphical depiction illustrating the role of microbial fermentation in a circular economy. Microbial fermentation valorizes resources back toward high-value products, fuels, and platform chemicals while detoxifying waste and generating biomass, with side stream applications such as fertilizer or animal feed. Images are obtained from open source resources including Pixabay and Openclipart.