Using microbial fermentation to increase the content of free amino acids and short peptides in the organic fertilizer for castor bean meal can effectively promote plant growth and improve fruit quality.Using free amin...Using microbial fermentation to increase the content of free amino acids and short peptides in the organic fertilizer for castor bean meal can effectively promote plant growth and improve fruit quality.Using free amino acid and short peptide content as an indicator,through single factor and response surface optimization experiments,the process parameters(moisture content,fermentation time and inoculum quantity)of castor meal solid-state fermentation were optimized.The best process parameters for the solid-state fermentation were:the moisture content 62%,the fermentation time 20 d,and the inoculum quantity 0.23%.The moisture content had the greatest impact on the conversion rate of free amino acids and short peptides,and the protein conversion rate reached 65.6%.The scale-up experiment under the optimal conditions showed that the solid-state fermentation using the inoculum had a significant beneficial effect compared with other fermentation methods.The fermentation of castor cake fertilizer provides a theoretical and practical basis for production feasibility,and has important guiding significance for the effective utilization of castor bean meal.展开更多
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 dr...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 DTO: 133-E8 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 Cu2+ and Fe2+ 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 study, it has been found that Chrysophlum albidum is suitable for the cultivation of Aspergillus niger and has great potential for citric acid production and could be exploited to promote certain industrial applications of underutilized fruits in Nigeria. This can be an application of waste to wealth as well as a way of minimizing agro-based environmental pollution for a cleaner environment.展开更多
基金Special Fund for International Cooperative Research of Qilu University of Technology(QLUTGJHZ2018010)。
文摘Using microbial fermentation to increase the content of free amino acids and short peptides in the organic fertilizer for castor bean meal can effectively promote plant growth and improve fruit quality.Using free amino acid and short peptide content as an indicator,through single factor and response surface optimization experiments,the process parameters(moisture content,fermentation time and inoculum quantity)of castor meal solid-state fermentation were optimized.The best process parameters for the solid-state fermentation were:the moisture content 62%,the fermentation time 20 d,and the inoculum quantity 0.23%.The moisture content had the greatest impact on the conversion rate of free amino acids and short peptides,and the protein conversion rate reached 65.6%.The scale-up experiment under the optimal conditions showed that the solid-state fermentation using the inoculum had a significant beneficial effect compared with other fermentation methods.The fermentation of castor cake fertilizer provides a theoretical and practical basis for production feasibility,and has important guiding significance for the effective utilization of castor bean meal.
文摘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 DTO: 133-E8 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 Cu2+ and Fe2+ 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 study, it has been found that Chrysophlum albidum is suitable for the cultivation of Aspergillus niger and has great potential for citric acid production and could be exploited to promote certain industrial applications of underutilized fruits in Nigeria. This can be an application of waste to wealth as well as a way of minimizing agro-based environmental pollution for a cleaner environment.
