Kinetics Growth and Recovery of Valuable Nutrients from Selangor Peat Swamp and Pristine Forest Soils Using Different Extraction Methods as Potential Microalgae Growth Enhancers.

Nor Suhaila Yaacob,Victor S Kuwahara,Maegala Nallapan Maniyam,Nobuyuki Kawasaki,Fridelina Sjahrir,Mohd Fadzli Ahmad,Emi Fazlina Hashim,Wan Muhammad Ikram Wan Mohd Zamri,Hasdianty Abdullah,Kazuhiro Komatsu

doi:10.3390/molecules26030653

Abstract

Soil extracts are useful nutrients to enhance the growth of microalgae. Therefore, the present study attempts for the use of virgin soils from Peninsular Malaysia as growth enhancer. Soils collected from Raja Musa Forest Reserve (RMFR) and Ayer Hitam Forest Reserve (AHFR) were treated using different extraction methods. The total dissolved nitrogen (TDN), total dissolved phosphorus (TDP), and dissolved organic carbon (DOC) concentrations in the autoclave methods were relatively higher than natural extraction with up to 132.0 mg N/L, 10.7 mg P/L, and 2629 mg C/L, respectively for RMFR. The results of TDN, TDP, and DOC suggested that the best extraction methods are autoclaved at 121 °C twice with increasing 87%, 84%, and 95%, respectively. Chlorella vulgaris TRG 4C dominated the growth at 121 °C twice extraction method in the RMRF and AHRF samples, with increasing 54.3% and 14%, respectively. The specific growth rate (µ) of both microalgae were relatively higher, 0.23 d−1 in the Ayer Hitam Soil. This extract served well as a microalgal growth promoter, reducing the cost and the needs for synthetic medium. Mass production of microalgae as aquatic feed will be attempted eventually. The high recovery rate of nutrients has a huge potential to serve as a growth promoter for microalgae.

Highlights

The slight increase of Total Dissolved Nitrogen (TDN) observed from 1 h to 4 h for Raja Musa Forest Reserve (RMFR), but the value decreased between 4 h and 24 h
Almost all results presented in this study demonstrated that the soil sample in the 120 ◦ C twice autoclaved method showed the highest nutrient extraction with the RMFR sample as the best soils to be used for microalgae growth enhancement
The analysis showed the promising result of enhanced microalgae growth with additional enrichment from treated forest soil extracts

Summary

Introduction

Microalgae have many beneficial industrial applications especially in the formulation of cosmetics. There is a need to uncover natural and cost-effective nutrient supplements that will enhance microalgae growth in large scale. Soil contains many valuable nutrients, and the present study embarks on the discovery of soil extracts from local habitats which could support the growth of microalgae. This is the first study to the best of our knowledge where reserved forest soils were used as nutrient sources for microalgal growth. Previous studies have established that synthetic nitrogen source was

Objectives

Methods

Results

Discussion

Conclusion