Converting corn wet-milling effluent into high-value fungal biomass in a biofilm reactor

Use of Organic Wastes and Industrial By-Products to Produce Filamentous Fungi with Potential as Aqua-Feed Ingredients

Organic-rich waste and industrial by-product streams, generated in enormous amounts on a daily basis, contain substantial amounts of nutrients that are worthy of recovery. Biological conversion of organic-waste streams using filamentous fungi is a promising approach to convert nutrients into value-added bioproducts, such as fungal biomass. High-protein fungal biomass contains different kinds and levels of amino acids, fatty acids, immunostimulants, antioxidants, pigments, etc., which make it a potential choice for application in animal feed supplementation. Considering the challenges long faced by the aquaculture industry in fishmeal production due to the increasing prices and environmental concerns, the aquaculture industry is forced to provide alternative protein-rich sources to replace conventional fishmeal. In this review, the possibilities of utilization of filamentous fungi biomass cultivated on organic-rich waste streams, as an alternative nutrient source in fish feed, were thoroughly reviewed.

Water reclamation and value-added animal feed from corn-ethanol stillage by fungal processing

Rhizopus oligosporus was cultivated on thin stillage from a dry-grind corn ethanol plant. The aim of the research was to develop a process to replace the current energy-intensive flash evaporation and make use of this nutrient-rich stream to create a new co-product in the form of protein-rich biomass. Batch experiments in 5- and 50-L stirred bioreactors showed prolific fungal growth under non-sterile conditions. COD, suspended solids, glycerol, and organic acids removals, critical for in-plant water reuse, reached ca. 80%, 98%, 100% and 100%, respectively, within 5 d of fungal inoculation, enabling effluent recycle as process water. R. oligosporus contains 2% lysine, good levels of other essential amino acids, and 43% crude protein - a highly nutritious livestock feed. Avoiding water evaporation from thin stillage would furthermore save substantial energy inputs on corn ethanol plants.

Innovative biorefinery concept for sugar-based ethanol industries: production of protein-rich fungal biomass on vinasse as an aquaculture feed ingredient

This study examined the potential of producing a protein-rich fungus, Rhizopus microsporus (var. oligosporus), as an aquaculture feed ingredient on vinasse generated during sugar-based ethanol fermentation. Optimization studies showed prolific fungal growth at pH 5.0 and 30 degrees C on vinasse with nutrient (nitrogen and phosphorus) supplementation. The molasses-vinasse resulted in the highest specific fungal biomass yield of 0.21 (g biomass increase/(g initial biomassxg soluble chemical oxygen demand (SCOD) removed)). Organic and inorganic matters were significantly reduced, e.g., 42.02% SCOD and 24.41% total dissolved solids. Thus, the treated effluent could be recycled as process water or used for land applications. The fungal biomass was found to have 45.55% crude protein with significantly high amino acids, arginine and threonine. The integration of innovative fungal technology with sugar-based ethanol production could provide an opportunity for producing food-grade fungal protein for animal feed application with simultaneous water reclamation.