Table 2: Studies comprising of the enhancement strategies used for β-glucosidase production.

S. no.Strain used and enzymes Enhancement strategies ConclusionReference

1Aspergillus aculeatus β-glucosidase 1A recombinant T. reesei strain, X3AB1 under the control of xyn3 promoter63- and 25-fold higher β-glucosidase activity against cellobiose[38]
2β-glucosidase from Periconia spp.Heterologous expression in T. reesei Around 10.5-fold (23.9 IU/mg) higher β-glucosidase activity
A very high total cellulase activity (about 39.0 FPU/mg)
3T. reesei, Bgl2Mutational studies and engineering of active site residues Mutants, P172L, and P172L/F250A showed enhanced / and values by 5.3- and 6.9-fold
Also, mutant L167W had the best synergism with T. reesei in cellulosic biomass degradation
4T. reesei (bglI)Overexpression in P. pastoris GS115 under methanol-inducible alcohol oxidase promoter and S. cerevisiae secretory signal peptide.
β-glucosidase expression was 0.3 mg/mL and the maximum activity was 60 U/mL[39]
5β-glucosidase 1 (BGL1)Use of xyn3 and egl3 promoters through homologous recombination
4.0- and 7.5-fold higher β-glucosidase activity[70]
6T. citrinoviride mutantsMutational studies, use of ethidium bromide and ethyl methyl sulphonate as mutagensSecretion of endoglucanase, β-glucosidase and cellobiase was found to be 2.14-, 2.10-, 4.09-, and 1.73-fold higher[28]
7Thermostable β-glucosidase (cel3a)cel3a from Talaromyces emersonii was expressed in T. reesei High specific activity against p-nitrophenyl-β-D-glucopyranoside ( , 512 IU/mg) and was competitively inhibited by glucose (ki, 0.254 mM) and displayed transferase activity[40]
8BGL4 from H. grisea Overexpression of BGL4 in T. reesei or 
T. viride
Improvement in cellulose saccharification by 1.4–2.2 times[43]
9T. reesei Rut C-30Temperature and pH profiling studies 0.02% Tween-80 concentration was optimum, pH 5.0 and temperature (31°C) initially (for 18 h) was optimum for maximum production of cellulase and β-glucosidase[89]