Turning losses into opportunities: waste valorization and its potential application in the production of Philippine commodities

Abstract

This paper systematically reviewed the current technological advancements in the valorization of different wastes and by-products as raw materials for major industries in the Philippines. Such innovations mitigated environmental concerns, enhanced the value and sustainable utilization of by-products, and addressed issues of resource depletion. All articles that were considered in this review were thoroughly investigated, passed the exclusion criteria, and were divided according to the application of the product in the following industries: agriculture, food, and biofuel. The paper identified food wastes, organic industrial wastes, agricultural by-products, municipal wastes, and pharmaceutical by-products as the key sources for valorization. Processes including microbial fermentation, enzymatic digestion, dehydration, enzyme extraction, and homogenization had been explored to convert agricultural commodities, including growth media, substrates, fertilizers, and foodstuffs. In the food industry, valorization focused on the utilization of the nutritional value of by-products and the extraction of bioactive compounds. Emerging valorization methods to obtain these desired compounds included microwave-assisted extraction, microbe-assisted bioconversion of bio-based compounds, drying and milling, and fermentation, among others. For bioethanol production, the integration of alkali/acid and autohydrolysis pretreatments was combined with microwave or ultrasonic assistance techniques as well as simultaneous saccharification and co-fermentation. In biodiesel production, a synergistic approach involving acid pretreatments, bio-, nano-, or alkaline catalysts, and assisted transesterification methods had been adopted. In conclusion, the wide range of applications of advanced valorization techniques to diverse waste and by-product streams was being rigorously explored. This approach drove the sustainable production of high-value products and opened new avenues for industrial applications, paving the way to a more sustainable and resource-efficient future. Ultimately, future research focusing on optimized valorization techniques to enhance the efficiency and scalability of waste by-product utilization in the Philippines was recommended.