African Journal of Biotechnology Vol. 4 (7), pp. 657-659, July 2005          
ISSN 1684–5315 © 2005 Academic Journals

Short Communication

Production of ethanol from Carica papaya (pawpaw) agro waste: effect of saccharification and different treatments on ethanol yield

AKIN-OSANAIYE, B.C.¹, NZELIBE, H.C.²* and AGBAJI,  A.S.¹

¹National Research Institute for Chemical Technology Private Mail Bag 1052, Zaria, Kaduna State Nigeria.

²Biochemistry Department, Ahmadu Bello University Zaria, Kaduna State, Nigeria.

*Corresponding Author’s E-mail: zeechuks@yahoo.com.

Accepted March, 2005

A study was carried out on yeast fermentation of carica papaya (pawpaw) agricultural waste using dried active baker's yeast and brewer's yeast strain (Sacchromyces cerevisiae). The pawpaw considered as an agricultural waste was the tapped ripe pawpaw fruit harvested after the tapping of papain. Effect of different yeast strains on the percentage yield of ethanol was investigated. The effects of yeast concentration, saccharification and different nutrient supplements as they relate to the optimization of the ethanol yield were also carried out. The fermented pawpaw yielded ethanol contents of 3.83 to 5.19% (v/v). The reducing sugar in the pawpaw was determined before and after saccharification. The reducing sugar was highest after 48 h of saccharification using Aspergillus niger. The value recorded was 7.6 to 13.6 g/100g. Brewers yeast gave a higher ethanol yield than bakers yeast. Saccharification  for 48 h  coupled with nutrient supplements significantly increased the ethanol yield.

Key words: Paw-paw agrowaste, bakers yeast, brewers yeast, fermentation, pH, temperature, saccharification.