## 3 Results and Discussions
### Characterization of \(\varepsilon\)-Polyllysine  
\({}^{1}\)H NMR of \(\varepsilon\)-Polyllysine in D\({}_{2}\)O Isolated from _B. licheniformis_ PL26  
Protons (H\({}^{\mathrm{a}}\), H\({}^{\mathrm{c}}\)) attached to \(\alpha\)-amino groups arrived together as broad singlet at \(\delta\) 3.76 ppm and protons (H\({}^{\mathrm{b}}\), H\({}^{\mathrm{d}}\)) attached to \(\varepsilon\)-amino groups arrived together as broad singlet at \(\delta\) 3.14 ppm. Protons attached to \(\beta\) and \(\beta^{\prime}\) carbons come at \(\delta\) 1.75 ppm as broad singlet. While the other protons attached to carbons come at \(\delta\) 1.47 ppm (4H, \(\varepsilon\) and \(\varepsilon^{\prime}\)) and \(\delta\) 1.30 ppm (4H, \(\gamma\) and \(\gamma^{\prime}\) respectively  
Figure 4: Fourier transform infrared spectroscopy (FTIR) spectra of purified PHA recovered from _Bacillus licheniformis_.  
Figure 5: Fourier transform infrared spectroscopy (FTIR) spectra of standard PHA procured from Sigma Aldrich.  
(Figure 6). Overall, the peaks showing peptide linkage between \(\alpha\)-carboxyl group and the \(\varepsilon\)-amino group, confirming the structure as \(\varepsilon\)-polylysine.  
As per [PERSON] et al., 2010, chemical shift of \(\varepsilon\)-H in the \(\varepsilon\)-polylysine units \(\delta_{\varepsilon\mathrm{H}}\) and at the N-terminal \(\delta^{\prime}_{\varepsilon\mathrm{H}}\) are 3.097 and 2.863 of 5 kDa \(\varepsilon\)-polylysine protein [39]. However, similar results were obtained in the present case, wherein chemical shift of \(\varepsilon\)-H in the \(\varepsilon\)-polylysine units, \(\delta_{\varepsilon\mathrm{H}}\) is at \(\delta\) 3.14 ppm, which are in similar range with respect to the mentioned reports.  
The described process showed the potential of utilizing _Bacillus licheniformis_ for the production of PHA (64.59% w/w w.r.t cell dry mass i.e., 1.1 g/L P(3 HB-co-3 HV)) as well as \(\varepsilon\)-polylysine (0.2 g/L) using crude glycerol as the carbon source. In addition, there are no such reports as per our knowledge wherein two polymers are produced at a time in the same fermentation broth. Previously, [PERSON] et al., 2014 reported microbial synthesis of such polymer (P(3 HB-co-3 HV)) by _Halomonas hydrothermals_ (MTCC accession no. 5445) from seaweed derived levulinic acid at a concentration of 57.5% PHA/dry cell weight and [PERSON] et al., 2011 reported microbial synthesis of PHA from biodiesel by-products i.e., from crude glycerol and _Jatropha_ deoiled cake hydrolysate at a concentration of 75% PHA/dry cell weight. However, further optimization will be required for efficient production of PHA and \(\varepsilon\)-polylysine at larger scale.  
The most important parameter responsible for cost of the production in PHA is substrate for carbon and energy source. The economic feasibility of PHA would depend on few important factors like growth rate of microbe for generation of biomass, substrate cost and recovery process including the solvent involved. However, production of other biopolymer along with PHA in the fermentation medium will have additional advantage in further reducing the production cost. PHA production from biodiesel waste stream can reduce production cost and at the same time solves the problem of waste disposal. In order to increase the PHA yield, the concentration of carbon source and other nutrient source desired for the microbial production may be optimized.  
Figure 6: \({}^{1}\)H NMR of \(\varepsilon\)-PL in D\({}_{2}\)O isolated from _Bacillus licheniformis_.