苹果渣基质柠檬酸高产菌株选育

Screening of Citric Acid High-Yielding Aspergillus niger with Apple Pomace Base

分别以固态苹果渣、苹果渣固态酶解物、苹果渣酶解液和10%葡萄糖溶液为发酵基质研究了17株野生黑曲霉的柠檬酸产生能力,并对获得的4株柠檬酸高产菌进行了诱变育种。结果表明:17株黑曲霉在4种发酵基质中均能良好生长并发酵产生柠檬酸,不同菌株在同一发酵基质中产酸能力间存在差异。FG17、FG23、FG26、FG30等4株菌苹果渣基质柠檬酸产生能力较高,且在4种不同发酵基质中产酸性能稳定。4株菌分别经紫外线和60Co-γ射线诱变后得到的正向突变株柠檬酸产率均显著提高,突变株中FG26-15-4(UV)发酵苹果渣后柠檬酸产率最高,达11.32%,FG23-13-3(γ)发酵苹果渣酶解液后柠檬酸产率最高,达2.73 mg/mL,均高于现有研究报道,可作为不同类型苹果渣基质柠檬酸发酵用菌种。

Production capability of citric acid of 17 wild type Aspergillus niger （Asn） strains was studied in bases of solid apple pomaee, solid zymolytie substance of apple pomace, zymolytic liquid of apple pomace, and 10% glucose solution as fermentation substrate, and 4 obtained citric acid high - yielding strains were screened breeding after mutation. The results showed that all 17 Asn strains grew well in 4 fermentation substrates, however, different strain had different acid producing capability in the same fermentation substrate. Citric acid producting capability of FG17, FG23, FG26, and FG30 in apple pomace substrate was fairly high, and acid producing performance was stable in 4 different fermentation substrates. After mutated with UV and Co-γ, ray the citric acid production rate of every apositive mutant was obviously increased; among them the citric acid producing rate of FG26-15-4-UV to ferment apple pomaee was the highest, about 11.32% , and FG23-13-3 （γ） to ferment zymolytic liquid of apple pomace was the highest, about 2.73 mg/mL; they all higher than the existing reported study, and can be used fermentation strain seeds for different types of apple pomace to produce citric acid.