Biotechnological potential of agro-industrial wastes for protein enrichment by solid-state fermentation using Aspergillus niger

This study is to assess the biotechnological potential of agro-industrial wastes of pineapple(Ananas comosus),sweet potato(Ipomoea batatas)and watermelon(Citrullus lanatus)for protein enrichment by solid-state fermentation using Aspergillus niger.Spore suspensions of A.niger were prepared with potato dextrose broth that had been supplemented with sodium chloride,ammonium nitrate and thiamine,and adjusted to pH of 5.Initial protein contents of sterile and non-sterile wastes of the pineapple,sweet potato,and watermelon were determined by the Kjeldahl method.The remaining sterile and non-sterile wastes was inoculated with spore suspensions of A.niger and incubated at temperature of 24℃ under conditions of solid-state fermentation for 14 days.Protein contents of the inoculated sterile and non-sterile wastes were determined after 7 and 14 days.The sterile wastes of pineapple,sweet potato and watermelon recorded initial percentage protein contents of 4.37,4.39,and 10.89,respectively,whereas their corresponding non-sterile wastes recorded initial percentage protein contents of 3.76,4.00,and 10.16,respectively.The results further show that percentage increase in protein content of sterile wastes after 14 days of fermentation were pineapple,35.01%;sweet potato,27.60%;and watermelon,64.40%.Percentage increase in protein content of non-sterile wastes after 14 days of fermentation were pineapple,72.34%;sweet potato,85.25%;and watermelon,80.51%.These findings affirm the biotechnological potential of pineapple,sweet potato and watermelon wastes and the importance of fungi as agents for protein enrichment of agro-industrial wastes.

The biotechnological potential of using mono-and co-cultures of Aspergillus niger van Tieghem and Trichoderma viride Pers ex Fr.to enhance the protein content of cassava(Manihot esculenta Crantz)peels by solid substrate fermentation

The application of fungal biotechnology for nutrient value addition and improvement of agro-industrial wastes is critical in the development of protein-rich feed for livestock.This study evaluated conventional methods for protein enrichment of cassava peels by solid substrate fermentation using mono-and co-cultures of Aspergillus niger and Trichoderma viride.Sterile and non-sterile cassava peels inoculated with mono-cultures of A.niger or T.viride and co-cultures of A.niger and T.viride were spontaneously fermented for 21 days at 24℃.Fermented substrates were harvested at 0,7,14,and 21 days intervals,then oven-dried at 60℃,milled in a blender and further assayed for ash,carbohydrate,crude fibre,fat,and protein contents.Results showed that percentage increase in protein contents after 21 days incubation of sterile cassava peels were 71.02%(for mono-culture of A.niger)and 71.64%(for mono-culture of T.viride);co-culture of A.niger and T.viride yielded a 129.00%increase in protein.Enhanced percentage increase in protein content of the non-sterile cassava peels was 126.80%(for mono-culture of A.niger)and 168.34%(for mono-culture of T.viride)in contrast with 63.47%obtained for the co-culture of A.niger and T.viride in non-sterile cassava peels,which was attributable to possible antibiosis due to microbial competition.Ash content significantly(p≤0.05)increased for 21 days while carbohydrate,crude fibre and fat contents in both sterile and non-sterile cassava peels decreased over the same period.These findings underscore the fact that protein content of cassava peels can be significantly(p≤0.05)enriched through fungal biotechnology to produce value-added feed supplement for livestock.The practical implications of these findings are discussed.