Factors Affecting Yield and Safety of Protein Production from Cassava by Cephalosporium eichhorniae

Single-cell proteins

Both photosynthetic and nonphotosynthetic microorganisms, grown on various carbon and energy sources, are used in fermentation processes for the production of single-cell proteins. Commercial-scale production has been limited to two algal processes, one bacterial process, and several yeast and fungal processes. High capital and operating costs and the need for extensive nutritional and toxicological assessments have limited the development and commercialization of new processes. Any increase in commercial-scale production appears to be limited to those regions of the world where low-cost carbon and energy sources are available and conventional animal feedstuff proteins, such as soybean meal or fish meal, are in short supply.

Evaluation of F+ RNA and DNA coliphages as source-specific indicators of fecal contamination in surface waters

Male-specific (F+) coliphages have been investigated as viral indicators of fecal contamination that may provide source-specific information for impacted environmental waters. This study examined the presence and proportions of the different subgroups of F+ coliphages in a variety of fecal wastes and surface waters with well-defined potential waste impacts. Municipal wastewater samples had high proportions of F+ DNA and group II and III F+ RNA coliphages. Bovine wastewaters also contained a high proportion of F+ DNA coliphages, but group I and IV F+ RNA coliphages predominated. Swine wastewaters contained approximately equal proportions of F+ DNA and RNA coliphages, and group I and III F+ RNA coliphages were most common. Waterfowl (gull and goose) feces contained almost exclusively F+ RNA coliphages of groups I and IV. No F+ coliphages were isolated from the feces of the other species examined. F+ coliphage recovery from surface waters was influenced by precipitation events and animal or human land use. There were no significant differences in coliphage density among land use categories. Significant seasonal variation was observed in the proportions of F+ DNA and RNA coliphages. Group I F+ RNA coliphages were the vast majority (90%) of those recovered from surface waters. The percentage of group I F+ RNA coliphages detected was greatest at background sites, and the percentage of group II F+ RNA coliphages was highest at human-impacted sites. Monitoring of F+ coliphage groups can indicate the presence and major sources of microbial inputs to surface waters, but environmental effects on the relative occurrence of different groups need to be considered.

Production of Microbial Biomass Protein from Potato Processing Wastes by Cephalosporium eichhorniae

The use of Cephalosporium eichhorniae 152 (ATCC 38255) (reclassified as Acremonium alabamense ; see Addendum in Proof), a thermophilic, acidophilic, amylolytic fungus, for the conversion of potato processing wastes into microbial protein for use as animal feed was studied. The fungus was not inhibited by α-solanine or β-2-chaconine, antimicrobial compounds in potatoes, or by morpholine or cyclohexylamine (additives to steam used in the peeling process) at levels likely to be encountered in this substrate. Mixed effluent from holding tanks at a potato-processing plant contained about 10 9 bacteria per ml and inhibited fungal growth. The fungus grew well on fresh potato wastes containing up to 5% total carbohydrate and utilized both starch and protein at 45°C and pH 3.75. On potato homogenate medium containing 2% carbohydrate (about 14% fresh potato) supplemented with monoammonium phosphate (0.506 g/liter) and ferric iron (0.1 g/liter), with pH control (at 3.75) and additional nitrogen supplied by the automatic addition of ammonium hydroxide, typical yields were 0.61 g (dry weight) of product and 0.3 g of crude protein per g of carbohydrate supplied. An aerobic, spore-forming bacterium, related to Bacillus brevis , commonly contaminated nonsterilized batch cultures but was destroyed by heating for 15 min at 100°C.