Citric Acid Production Potential of <i>Aspergillus niger</i> Using <i>Chrysophyllum albidum</i> Peel

Abstract

The production of citric acid using Chrysophyllum albidum an indigenous under-utilized fruit waste peel and genetically characterized strains of Aspergillus niger was carried out. The Chrysophyllum albidum peel was dried, sieved to remove dirt, dry milled and the powder used as substrate for citric acid production. Thirteen fungal isolates were obtained from soil samples and decayed agricultural waste by spread plate technique and screened for citric acid producing capabilities on Czapek dox agar. Citric acid producing capability of the isolates revealed a wide yellow zone around the inoculated colonies. Two (F1 and F3) out of the thirteen isolates exhibited positive reactions and were identified based on their cultural, morphological and molecular characteristics. The fungal species were identified using PCR as Aspergillus niger DTO: 133-E8 and Aspergillus niger DTO: 131-H5. Their cultural/growth optimal conditions were determined through Solid State Fermentation of the substrate using two species of the test organism. The effects of fermentation period examined revealed, Aspergillus niger which produced the highest amount of citric acid 15.7 ± 0.08 g/l, lower reducing sugar and final pH of 2.1 and 121.5 ± 0.31 g/l respectively after 192 h of growth at 30˚C. Aspergillus niger DTO: 131-H5 showed highest amount of citric acid 10.2 ± 0.22 g/l, lower reducing sugar and final pH of 2.4 and 128.5 ± 0.15 g/l respectively after 192 h of growth at 30˚C. Maximum concentration of citric acid ranging between 16.3 ± 0.30 g/l and 12.6 ± 0.11 g/l with reducing sugar 125.4 ± 0.11 g/l and 127.2 ± 0.03 g/l was achieved at an initial pH of 5.5. Methanol was used to stimulate citric acid production (0% -3% (v/v)) and was found to be effective at 2% (v/v) level with 21.2 ± 0.20 g/l of citric acid produced with residual sucrose concentration of 129.5 ± 0.44 g/l. The effect of trace element on citric acid production showed that Cu 2+ and Fe 2+ stimulated citric acid production; while other ions reduced citric acid production. There was a statistically significant difference (P > 0.05) between the citric acid produced with the various parameters investigated in this research. From the

USE OF MULBERRY POMACE AS SUBSTRATE FOR CITRIC ACID PRODUCTION BY Aspergillus niger MT-4

“…The maximum increases in concentrations of both CA and FB were achieved in the first four days of fermentation. These results are similar to those reported in previous studies (Kareem et al 2010, Taskin et al 2013, Dienye et al 2018 showing that incubation time affects cell growth and CA synthesis in A. niger. On day 5, CA concentration and CA yield (Yp/s) were determined as 24.6 g/L and 0.2 g CA/g MP, respectively.…”

“…A continuous drop in culture pH up to the end of the 5 th day could be ascribed to the production of organic acids, especially CA. Similar decreases in culture pH during CA production were also reported in the previous studies (Ali et al 2002, Dienye et al 2018. Increment in culture pH after the 5 th day might be attributed to the releasing into the culture of some alkaline compounds due to fungal cell lysis.…”

Citric acid Production from Agricultural Wastes using Aspergillus niger Isolated from some Locations within Kaduna Metropolis, Nigeria

“…Biotechnology has been key in exploiting the diversity and/or metabolic activities of different microorganisms in fermenting wide range of agricultural wastes to produce several useful products such as crude enzymes (Saha and Santra, 2014) electrical energy using microbial fuel cell (MFC) (Aderiye et al, 2018); chemicals like biogas, bioethanol (Muradin and Foltynowicz, 2014) and organic acids (like citric acid) (Muharani et al, 2014;Dienye et al, 2018). Citric acid (2-hydroxy-1, 2, 3tricarboxylic acid) is in high demand in different industries as food, chemical, beverage, cosmetic and pharmaceutical for stabilization, flavour enhancement, emulsification, preservation, anti-oxidation, acidulation, as synergistic agent and plasticizer (Soccol et al, 2006;Maharani et al, 2014).…”

“…However, some potentials like easy to handle, ability to produce higher acid per unit time and ability to utilize cheap raw biomass (Schuster et al, 2002;Kareem and Rahman, 2011), has made Aspergillus. niger most preferred organism in the production of citric acid (Lotfy et al, 2007;Maharani et al, 2014;Dienye et al, 2018). Aspergillus niger has been used in the industrial preparation of citric acid (Max et al, 2010).…”

“…The thermotolerant abilities of A. niger enable growth over a wide temperature range from 6 to 47 o C with a preferred optimum temperature at 35-37 o C (Schuster et al, 2002.). Using agricultural waste for producing valuable products like citric acid in recent time has not only increased the sustenance of the acid for industrial application, but also enhanced control and management of environmental pollution and littering (Dienye et al, 2018). Cheap agricultural wastes like rice straw, wheat straw and potato peel powder are among substrates that are reported promising at cost reduction in citric acid production (Haq et al, 2004;Ali et al, 2012;Femi-Ola and Atere, 2013;Meenakshi and Kumaresan, 2014).…”