Apple pomace: a versatile substrate for biotechnological applications.
ABSTRACT Apple pomace is the processing waste generated after apple juice manufacturing and represents up to 30% of the original fruit. This solid residue consists of a complex mixture of peel, core, seed, calyx, stem, and soft tissue. This residual material is a poor animal feed supplement because of its extremely low protein content and high amount of sugar. The application of agroindustrial by-products in bioprocesses offers a wide range of alternative substrates, thus helping solve pollution problems related to their disposal. Attempts have been made to use apple pomace to generate several value-added products, such as enzymes, single cell protein, aroma compounds, ethanol, organic acids, polysaccharides, and mushrooms. This article reviews recent developments regarding processes and products that employed apple pomace as a substrate for biotechnological applications.
Article: Utilization of different agro-industrial wastes for sustainable bioproduction of citric acid by Aspergillus niger[show abstract] [hide abstract]
ABSTRACT: In view of ever growing demand of citric acid, there is an urgent need to look for inexpensive and novel substrates for feasible production of citric acid. In this context, the present study was carried out to evaluate the potential of different agro-industrial wastes for hyper production of citric acid through solid-state and submerged fermentation by Aspergillus niger NRRL 567 and NRRL 2001. It was found that among all the solid substrates utilized, apple pomace with 66.0 ± 1.9 g/kg of dry substrate proved to be an excellent substrate for citric acid production by A. niger NRRL 567 at 72 h of incubation. A. niger NRRL 2001 resulted in slightly lower citric acid concentration of 61.0 ± 1.9 g/kg of dry substrate at the same incubation time. APS-1 (apple pomace ultrafiltration sludge-1) gave highest citric acid production rate of 9.0 ± 0.3 g/l and 8.9 ± 0.3 g/l of substrate by A. niger NRRL 567 and NRRL 2001 by submerged fermentation, respectively. Further study with apple pomace and apple pomace ultrafiltration sludge-1 by A. niger NRRL 567 was carried out. Addition of 3% (v/w) ethanol and 4% (v/w) methanol to apple pomace gave significantly higher citric acid values of 127.9 ± 4.3 g/kg and 115.8 ± 3.8 g/kg of dry substrate by A. niger NRRL 567 by solid-state fermentation. Higher citric acid values of 18.2 ± 0.4 g/l and 13.9 ± 0.4 g/l of apple pomace ultrafiltration sludge-1 were attained after addition of 3% (v/v) ethanol and 4% (v/v) methanol, respectively by A. niger NRRL 567. Apple pomace solid waste and apple pomace ultrafiltration sludge-1 thus proved to be an excellent source for citric acid production, of the different substrates chosen.Biochemical Engineering Journal 04/2011; · 2.64 Impact Factor