Integrated biovalorization of Pongamia pinnata seeds for sustainable biodiesel and bioethanol production

Sidra Rani; Zahid Anwar; Zafar Iqbal; Muddassar Zafar; Hafiz Muhammad Javed

doi:10.2478/pjct-2026-0004

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Integrated biovalorization of Pongamia pinnata seeds for sustainable biodiesel and bioethanol production

Green Sciences

Volume 28 (2026): Issue 1 (March 2026)

By: Sidra Rani, Zahid Anwar, Zafar Iqbal, Muddassar Zafar and Hafiz Muhammad Javed

Open Access

|Apr 2026

Figures & Tables

Fourier-transform infrared spectroscopy (FTIR) spectrum of P. pinnata seeds.

Alcohol to oil ratio used in the transesterification of P. pinnata oil (a), and Biodiesel after Washing the Oil & Transesterification Process (b). X-Axis represent the different alcohol to oil ratios used and SD was calculated for n = 3.

Contour (a) and 3D response surface plot (b) showing the interactive effects of incubation time (min) and substrate concentration (g) on glucose concentration activity during enzymatic hydrolysis of P. pinnata seed biomass. The red dot represents the experimental design point, while the color gradient indicates enzyme activity levels ranging from low (blue, 11.29 U mL−1) to high (red, 429.22 U mL−1). Actual factors were fixed at temperature = 60°C and acid concentration = 1.75%.

Contour (a) and 3D response surface plot (b) showing the interactive effects of temperature (°C) and substrate concentration (g) on glucose concentration during enzymatic hydrolysis of P. pinnata seed biomass. The red dot represents the experimental design point, while the color gradient indicates enzyme activity levels ranging from low (blue, 11.29 U mL−1) to high (red, 429.22 U mL−1). Actual factors were fixed at acid concentration = 2.5% and temperature 40°C.

Contour (a) and 3D response surface plot (b) showing the interactive effects of acid concentration (%) and temperature (°C) on glucose concentration during enzymatic hydrolysis of P. pinnata seed biomass. The red dot represents the experimental design point, while the color gradient indicates enzyme activity levels ranging from low (blue, 11.29 U mL−1) to high (red, 429.22 U mL−1). Actual factors were fixed at D: acid concentration = 2.5% and B: temperature 40°C.

Optimization of substrate concentration on glucose release and ethanol yield during fermentation. (a) Effect of varying substrate concentrations (0.5, 1.0, 1.5, and 2.0%) on glucose release (mg mL−1) over 72 h. (b) Corresponding ethanol yield (%) measured at different time intervals (12–72 h). Ethanol production increased steadily, reaching a maximum of 6.77% after 72 h, indicating efficient conversion of glucose into ethanol at optimal conditions.

Experimental design for RSM

SR #	Temperature (°C)	Time (min)	Acid conc. (%)	Substrate conc. (g)	Glucose conc. (mg mL^‒1)
1	30	20	3	1	35.201
2	30	20	3	4	59.110
3	30	60	0.5	1	130.112
4	30	60	0.5	4	71.211
5	30	20	0.5	1	77.341
6	30	20	0.5	4	80.322
7	60	40	1.75	2.5	177.109
8	60	40	1.75	2.5	181.214
9	30	60	3	1	44.221
10	60	40	4.25	2.5	11.298
11	60	40	1.75	5.5	123.765
12	60	40	0.25	2.5	149.246
13	60	10	1.75	2.5	69.776
14	60	80	1.75	0.5	101.209
15	30	60	3	4	14.117
16	60	40	1.75	0.5	120.328
17	20	40	1.75	2.5	116.821
18	90	20	0.5	1	260.671
19	60	40	1.75	2.5	178.109
20	90	20	0.5	4	329.432
21	90	60	0.5	1	363.119
22	100	60	1.75	2.5	429.220
23	60	40	1.75	2.5	179.402
24	60	40	1.75	2.5	177.712
25	90	60	3	1	285.996
26	90	20	3	1	248.556
27	90	20	3	4	306.245
28	60	40	1.75	2.5	180.127
29	90	60	0.5	4	350.478
30	90	60	3	4	229.492

Glucose yield (mg mL‒1) during enzymatic hydrolysis

Time	6 h	24 h	48 h	72 h
Enzyme conc.	mg mL^‒1	mg mL^‒1	mg mL^‒1	mg mL^‒1
Control	80.01	80.02	80.04	80.04
0.5 mL	70.91	72.11	108.31	110.12
1.0 mL	74.01	84.32	110.21	112.24
1.5 mL	81.41	96.89	112.22	115.12
2.0 mL	85.11	104.01	116.19	118.21

FTIR Spectrum of Pongamia pinnata seeds

Sr. #	Wave number (cm⁻¹)	Functional group	Bond
1	3273.11	Alcohol	O–H
2	2920.51	Alkane	C–H
3	2850.99	Alkane	C–H
4	1708.89	Carbonyl	C–O
5	1624.30	Alkenes	C–C
6	1405.47	Phenols	–OH bending vibrations, –C–O–H in-plane bending vibrations,–CH₃ out-of-plane bending vibrations, –CH₂ – wagging and twisting vibrations
7	1227.37	Amines	N–H, C–O (hemicellulose)
8	1020.53	Halogen	C–F (guaiacyl unit of lignin) and C–O (primary alcohol and cellulose)
9	756.02	Halogen	C–Cl

Seeds for sustainable biodiesel and bioethanol production

Source	Sum of squares	df	Mean square	F-value	p-value
Model	3.545 × 10⁺⁵	14	25319.56	78.65	<0.0001	Significant
A-temperature	2.655 × 10⁺⁵	1	2.655 × 10⁺⁵	824.65	<0.0001
B-time	1226.37	1	1226.37	3.81	0.0699
C-acid conc.	14299.02	1	14299.02	44.41	<0.0001
D-subs. conc.	45.74	1	45.74	0.1421	0.7115
AB	280.38	1	280.38	0.8709	0.3655
AC	45.81	1	45.81	0.1423	0.7113
AD	891.32	1	891.32	2.77	0.1169
BC	3673.57	1	3673.57	11.41	0.0041
BD	6855.05	1	6855.05	21.29	0.0003
CD	1.70	1	1.70	0.0053	0.9431
A²	42696.64	1	42696.64	132.62	<0.0001
B²	11642.50	1	11642.50	36.16	<0.0001
C²	9683.89	1	9683.89	30.08	<0.0001
D²	2324.56	1	2324.56	7.22	0.0169
Residual	4829.19	15	321.95
Lack of fit	4816.85	10	481.68	195.10	<0.0001	Significant
Pure error	12.34	5	2.47
Cor total	3.593 × 10⁺⁵	29

Coded and uncoded values of the variables for the Box–Behnken design

Sr. #	Coded values of variables	−α	−1	0	+1	+α
	Variables uncoded values
1	Temperature (°C)	30	60	80	90	100
2	Acid concentrations (%)	0.25	0.5	1.75	53	4.25
3	Time (min)	20	30	40	60	80
4	Substrate concentrations (g)	0.5	1	2.5	4	5.5

Model Summary

S	R-sq	R-sq (adjusted)	R-sq (predicted)
17.94	R ² = 98.66%	97.40%	93.70%

Regression Equation in Uncoded Units

Enzyme activity	=
+170.02
+117.61	A
+7.61	B
−27.07	C
+1.49	D
+4.05	AB
−1.69	AC
+7.46	AD
−15.15	BC
−19.70	BD
−0.3256	CD
+71.42	A²
−28.84	B²
−24.23	C²
−11.59	D²

References

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Articles in this issue

DOI: https://doi.org/10.2478/pjct-2026-0004 | Journal eISSN: 3072-0389

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Language: English

Page range: 44 - 59

Submitted on: Oct 26, 2025

Accepted on: Feb 8, 2026

Published on: Apr 27, 2026

Published by: West Pomeranian University of Technology, Szczecin

In partnership with: Paradigm Publishing Services

Publication frequency: Volume open

Keywords:

Bioethanol,

Biodiesel,

Biomass,

FTIR,

Pongamia pinnata ,

Valorization

Related subjects:

Industrial chemistry,

Biotechnology,

Chemical engineering,

Process engineering

© 2026 Sidra Rani, Zahid Anwar, Zafar Iqbal, Muddassar Zafar, Hafiz Muhammad Javed, published by West Pomeranian University of Technology, Szczecin
This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 License.

Volume 28 (2026): Issue 1 (March 2026)

Integrated biovalorization of Pongamia pinnata seeds for sustainable biodiesel and bioethanol production

Figures & Tables

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Experimental design for RSM

Glucose yield (mg mL‒1) during enzymatic hydrolysis

FTIR Spectrum of Pongamia pinnata seeds

Seeds for sustainable biodiesel and bioethanol production

Coded and uncoded values of the variables for the Box–Behnken design

Model Summary

Regression Equation in Uncoded Units

Paradigm

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