**3.9 Liquid peat formulation (with pellet suspension)**

The pellets mixed with suspension formulations and added with peat showed us increasing CFU's 5.0×108/gm (**Table 7** and **Figure 9**) than other formulations on the formulation day.

*Optimizing Shelf-life of* Pseudomonas fluorescens *after Freeze Drying DOI: http://dx.doi.org/10.5772/intechopen.108034*

#### **Figure 7.**

*Colonies in LB plate from 90% dextrose formulation.*


#### **Table 3.**

*Dextrose formulation.*


#### **Table 4.**

*Dextrose formulation.*


#### **Table 5.**

*Solid peat formulation.*

**Figure 8.**

*Colonies in LB plate from solid peat formulation.*

## **3.10 Shelf-life analysis**

In this research, we also revealed the shelf-life of LP microbes with different formulations such as dextrose, peat, and talc. Peat with centrifuged liquid cell


#### **Table 6.**

*Talc formulation.*


#### **Table 7.**

*Peat formulation with pellet suspension.*

#### **Figure 9.**

*Colonies in LB plate from liquid peat formulation.*


#### **Table 8.**

*Dextrose formulation shelf-life.*

suspension showed significant shelf-life up to 30 days. It showed 1.0×107 /gm CFU's. Rather the 5% (**Table 8** and **Figure 10**) and 10% LP (**Table 9** and **Figure 11**) and 95% and 90% dextrose showed no colonies on 07 days' shelf-life analysis. The LP and the peat mixture survived for 14 days with 4.0×104 /gm CFU's (**Table 10** and **Figure 12**). Previously, we showed that the talc formulations were not survived even a day and this proves that centrifuged pellet liquid suspension mixed with peat gives us the 60-day survival significant CFU's (**Table 11** and **Figure 13**).

### **4. Discussion**

The inclusive results of our experiments showed that *P. fluorescens* could survive initially with dextrose, solid peat, and talc carriers at room temperature. But *P. fluorescens* was not viable in dextrose carrier up to 1 week. Peat formulation was found as a

*Optimizing Shelf-life of* Pseudomonas fluorescens *after Freeze Drying DOI: http://dx.doi.org/10.5772/intechopen.108034*

**Figure 10.** *Shelf-life colonies in LB plate.*


#### **Table 9.**

*Dextrose formulation shelf-life.*

good carrier for formulating product of *P. fluorescens*. When LP was mixed with peat powder, it was observed cell number 4×104 per gram till 14 days. The best significant result was observed when peat was mixed with centrifuged cell pellet suspension; we observed 2×107 CFUs per gram surviving more than 60 days. Peat is very common used carrier material globally and has high content of organic matter, water holding capacity, and simply obtainable [19]. In previous study, it was found that peat showed good efficacy in formulation, and help colonization in plant roots when peat was used for bio formulation of *P. fluorescens* [20]. Nakkeeran et al. also observed similar potential results of peat-based formulation for *P. chlororaphis* shelf-life [21]. Therefore, we also reveal that peat with less moisture is the suitable carrier for centrifuged

#### **Figure 11.**

*Shelf-life colonies of 10% LP + 90% dextrose in LB plate.*


**Table 10.**

*Solid peat formulation shelf-life.*

cells suspension. Our research will be prospective to make new formulations and to increase the shelf-life and survival rate of soil microbes especially *P. fluorescens*.

#### **5. Conclusion**

From our results, we can conclude that centrifuged cells suspended in peat survived for long duration. Applying peat with suspended *P. fluorescens* may not hamper

#### *Optimizing Shelf-life of* Pseudomonas fluorescens *after Freeze Drying DOI: http://dx.doi.org/10.5772/intechopen.108034*

#### **Figure 12.**

*Shelf-life colonies of 95% peat+5% LP in LB plate.*


#### **Table 11.**

*Peat formulation with pellet suspension shelf-life.*

soil fertility, since peat is a universal bio carrier and sustains with all soil conditions. Even though we tried different carriers such as dextrose and talc, peat termed to be a suitable carrier for *P. fluorescens.*

In conclusion, although different types of carrier can be mixed with *P. fluorescens* for bioformulation, peat-based formulation showed good viability at room temperature.

**Figure 13.**

*Shelf-life of 70% peat+30% CaCO3 + 20 ml pellet suspension in LB plate.*
